Chapter 5: Micronutrients

By Mary Marian, DCN, RDN, FAND, FASPEN; Bahar Bakhshi, MS

Student contributor: Ame Proietti 

Introduction

Micronutrients include vitamins, minerals, and trace elements that are required in small amounts for normal growth and development and to support several bodily functions. Micronutrients perform a range of functions, such as supporting the synthesis of enzymes, hormones, and other biological compounds needed for growth and optimal function, including the metabolism of the macronutrients discussed in chapter 4.

Micronutrient deficiencies cause visible and dangerous health conditions. They also can contribute to less clinically notable reductions in energy level, mental acuity, and overall functional capacity, as well as an increased risk for other diseases and health conditions. Deficiencies are generally preventable through the consumption of a variety of foods, although certain populations (e.g., pregnant or lactating individuals, elderly adults, young children, individuals with food insecurity) might have difficulty correcting deficiencies with food alone.

Culinary medicine seeks to prevent or address micronutrient deficiencies through nutrition education, including increasing one’s knowledge of the nutrients in various foods, food fortification, and supplementation, and the development of culinary skills that support the preparation of diverse foods.

Micronutrients

Micronutrients—including vitamins, minerals, and trace elements—are inorganic compounds essential for health and wellness. The body is unable to synthesis or store many of these micronutrients, so to meet the body’s daily needs, these compounds must be obtained from one’s diet (through consumption of food and/or dietary supplements) and/or specialized nutrition support (enteral or parenteral nutrition).

Well-planned diets can ensure that healthy individuals consume adequate amounts of micronutrients. Various eating plans, such as the Mediterranean or the Dietary Approaches to Stop Hypertension (DASH) diets, are associated with preventing or managing various health conditions, including cardiovascular disease, hypertension, type 2 diabetes, and certain cancers. Fruits, vegetables, whole grains, nuts, and seeds form the foundation of these eating patterns.

These various foods provide micronutrients that play a key role in health and wellness. The principles of culinary medicine are grounded in the mantra “where health meets foods.” Micronutrient availability and, ultimately, their use by the body are influenced by many factors, including where food is grown and how it is transported, processed, and prepared. But it also is affected by one’s medical history and current health status.

Previous chapters have reviewed food preparation and cooking methods that promote the preparation of high-quality whole foods and meals. Furthermore, well-planned diets can ensure that healthy individuals consume adequate amounts of micronutrients. This chapter will review the key functions and recommended intake levels of micronutrients, factors that influence micronutrient availability and that may promote deficiency, food sources, and biomarkers for assessing status and need for possible supplementation. Also described are the use of popular diets by consumers and their impact on micronutrient provision.

Understanding the relationship between food and micronutrient provision is an essential component that aligns with the application of culinary medicine principles to promote disease prevention and management through the consumption and enjoyment of healthy, tasty food.

Micronutrient Needs

The Dietary Reference Intakes (DRIs)—created by the Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine and promoted in established guidelines—have set reference micronutrient intake values for all generally healthy Americans.¹ These values are based on age and sex. For women, values vary based on pregnancy and lactation. However, individual needs may be lower or higher than these reference values based on health status; therefore, it is important to assess one’s health status before determining interventions.

These standards are used in the design of food labels, for assessing an individual’s adequacy of nutrient dietary intake, and for planning diets. Knowing what the daily intake goals are is essential to know whether dietary intake is sufficient and if supplementation is needed to meet nutrient needs to promote optimal health and wellness.

The DRIs provide a set of recommended values used to assess adequacy of nutrient intake.^1-3 Included in this set of guidelines are:

• Adequate Intake (AI)
• Estimated Average Requirement (EAR)
• Recommended Dietary Allowance (RDA)
• Tolerable Upper Intake Level (UL)

A digital daily calculator is available to assist health-care professionals in evaluating the adequacy of intake.² This is useful to provide recommendations for achieving optimal micronutrient status.

The RDA values reflect the level of a specific nutrient that 98% of a generally healthy population needs.¹ This is because RDAs are set 2 standard deviations above the EAR values, which establishes a margin of safety for intake.

Food labels can provide valuable information to help consumers determine what micronutrients (and how much of them) are in a product. However, food labels can be confusing because they use the Daily Value (DV) or percent DV (%DV) instead of the DRIs.³ Although the DV is similar to the DRIs, the DV is not differentiated by age and sex, like the RDAs. Daily Values have been established by the US Food and Drug Administration (FDA), and before 2016, there was only 1 DV for each of the micronutrients.³

For example, the %DV labels for iron is 18 milligrams (mg). However, the RDA for adult men is 8 mg per day; for women, 18 mg per day reflects the RDA for premenopausal women, and the RDA decreases to 8 mg per day for postmenopausal women. This difference in values can be confusing for consumers when trying to determine which foods will help meet their nutritional needs.

Labels are also only required to reflect the DVs for calcium, vitamin D, potassium, and iron.³ The other micronutrients are not required to be listed, but they can be, at the discretion of the manufacturer.

The DVs reflect the percentage of a nutrient a product will provide as it relates to the “highest” RDA based on age and sex (see Figure 5.1). For example, related to iron, the %DV listed on a food label correlates with the RDA for premenopausal women (18 mg), which is the highest of the various RDAs for age and sex.

Vitamins

Vitamins can be obtained from a variety of different foods and are classified as either water soluble or fat soluble. Various mechanisms in the small intestine are responsible for the absorption of vitamins. A major difference between the 2 types of vitamins is that fat-soluble vitamins are absorbed with fat. The following discussion describes the role each vitamin plays in promoting health and wellness, in addition to reviewing: recommended intake levels, food sources, recommended biomarkers for assessing status, signs of deficiencies, and populations at risk.

Water-Soluble Vitamins

There are 9 water-soluble vitamins. They, in addition to other vitamins, play a role in metabolism, primarily as cofactors or coenzymes necessary in the formation and storage of energy (see Table 5.1). Although only needed in small quantities by the body, water-soluble vitamins cannot be synthesized or stored by the body. Thus, they are required daily to meet one’s needs; in some cases, deficiencies that increase risk for illness and death can develop very quickly.

Table 5.1. Water-Soluble Vitamin Functions^5-13

B vitamins
Thiamine (B1)	Required in energy transformation, synthesis of pentoses and reduced nicotinamide adenine dinucleotide phosphate (NADPH), and nerve conduction. Plays a major role in carbohydrate metabolism and serves as a magnesium-coordinated coenzyme for oxidative decarboxylation of α-ketoacids (e.g., pyruvate). Deficiencies can arise with alcohol abuse, diuretic use, and malabsorption.
Riboflavin (B2)	Primary function is as a component of the flavin mononucleotide and flavin adenine dinucleotide as an electron transport intermediary for oxidation-reduction reactions. Also has antioxidant properties. Deficiency is rare.
Niacin (B3)	Nicotinamide portion of nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate serves as a hydrogen donor or an electron acceptor for more than 200 enzymes involved in intermediary metabolism of amino acids, carbohydrates, and fatty acids. NADPH is required for activation of folate. Pellagra is the disease caused by niacin deficiency, which is rare in developed nations. Look for the 3 Ds: dermatitis, diarrhea, and dementia. Deficiencies may occur with malnutrition and malabsorption.
Vitamin B6 (3 forms: pyridoxine, pyridoxal, and pyridoxamine)	Coenzyme forms participate in more than 100 enzymatic reactions. Facilitates transamination and deamination. Important for cognitive development. Also assists with decreasing homocysteine levels. Pyridoxine is converted to the active coenzyme pyridoxal phosphate and coenzyme pyridoxamine to pyridoxamine phosphate.
Vitamin B12	Needed for the conversion of homocysteine to methionine. Elevated homocysteine levels have been linked with increased risk for cardiovascular disease, cerebral vascular accident, dementia, Alzheimer’s disease, and osteoporosis. When B12 is lacking, folate is “trapped” in its inactive form. B12 is also needed for erythrocyte synthesis. Deficiencies may occur with malabsorption, inadequate intake, and use of certain medications.
Other vitamins
Folic acid	Primary function is as a coenzyme in the transfer of single-carbon fragments from 1 compound to another for amino acid metabolism and nucleic acid synthesis. There is increased demand for folate during pregnancy, due to increased demand for DNA synthesis for embryonic development. Folate deficiency causes the misincorporation of uracil in place of thymine, leading to DNA fragility and strand breakage that cause neural tube defects (NTDs) during fetal development. Since the FDA mandated folate fortification of cereal and grain products in 1998, incidence of NTDs has declined.
Vitamin C	Antioxidant; synthesis of collagen, carnitine, and neurotransmitters; enhances intestinal absorption of nonheme iron, and immune-mediated and antibacterial functions of white blood cells. Deficiency can be caused by inadequate intake and malabsorption.
Pantothenic acid (PA)	As a component of coenzyme A, PA is involved in energy production from fat, carbohydrates, and ketogenic amino acids. Also required for the synthesis of bile salts, cholesterol, steroid hormones, and fatty acids. Deficiency is rare.
Biotin	Necessary for genetic expression of more than 2,000 enzymes; also needed as a cofactor for several carboxylase enzymes required for metabolic pathways, such as gluconeogenesis and fatty acid synthesis. Deficiency is rare because biotin can be synthesized by colonic microflora.

Table 5.2 illustrates the daily recommendations for water-soluble vitamin intake for adults based on sex and ULs. Rich food sources for each vitamin, in addition to recommended biomarkers for assessing micronutrient status, are also listed.

Table 5.2. Water-Soluble Vitamin Recommendations^5-13

Water-soluble vitamin	RDA/AI: adult men	RDA/AI: adult women	Tolerable Upper Intake Level	Rich food sources	Recommended biomarkers for assessing status
Thiamine	1.2 mg/d	1.1 mg/d	ND	Pork, fortified/enriched foods, sunflower seeds, wheat germ	Whole blood or erythrocyte thiamine diphosphate
Riboflavin	1.3 mg/d	1.1 mg/d	ND	Fortified/enriched foods, dairy	Erythrocyte glutathione reductase
Niacin	16 mg/d	14 mg/d	35 mg/d	Poultry, fish, beef, fortified/enriched foods	Urinary N1-methyl-nicotinamide and N1-methyl-2-pyridone-5-carboxamide
Pyridoxine (vitamin B6)	1.3 mg/d	1.3 mg/d	100 mg/d	Fortified/enriched foods, garbanzo beans, salmon	Plasma pyridoxal 5′-phosphate
Folic acid	400 mcg/d	400 mcg/d	1,000 mcg/d	Spinach, fortified foods such as cereals and pastas, lentils, legumes, asparagus	Red blood cell folate
Vitamin B12	2.4 mcg/d	2.4 mcg/d	ND	Liver, clams, oysters, fortified cereals, cottage cheese, animal products, fortified vegan foods	Methylmalonic acid levels; serum B12 levels; always assess folate status simultaneously
Pantothenic acid	5 mg/d	5 mg/d	ND	Beef liver, fortified/enriched foods, shitake mushrooms, sunflower seeds	Whole-blood pantothenic acid
Biotin	30 mcg/d	30 mcg/d	ND	Egg yolks, nuts, legumes	Urinary 3-hydroxyisovaleric acid
Vitamin C	90 mg/d Smokers: 125 mg/d	75 mg/d Smokers: 115 mg/d	2,000 mg/d	Citrus, tomatoes, strawberries, peppers	Plasma vitamin C or leukocyte vitamin C
Abbreviations: AI = Adequate Intake; d = day; ND = not determined; mcg = microgram; mg = milligram; RDA = Recommended Daily Allowance.

Given the body’s inability to store the water-soluble vitamins, deficiencies can develop quickly for a myriad of reasons. Table 5.3 reflects the populations at risk for deficiencies.

The small intestine is responsible for the digestion and absorption of most micronutrients. Therefore, any conditions that impair these functions or resections of the gastrointestinal tract can lead to the development of deficiencies. Chronic systematic inflammation also adversely affects metabolism of several water-soluble vitamins, including pyridoxine, folate, and vitamin B₁₂.^9,10 Furthermore, prescribed medications, disordered eating styles, alcohol abuse, and health status can lead to alterations in micronutrient status.

Table 5.3. Water-Soluble Vitamin Clinical Relevance Summary^5-13

Vitamin	Signs and symptoms	Conditions that increase risk	Repletion dose	Other notable details
Thiamine (B1)	Ocular abnormalities, nystagmus, gait ataxia, and mental status changes (Wernicke encephalopathy; wet or dry beriberi)	Bariatric surgery, malabsorptive disorders, protracted vomiting, alcohol abuse, malnutrition with or without hyper-metabolism, diuretics, dialysis	Varies: Suspected Wernicke encephalopathy: 100-200 mg/d IV or 3 times/d IM for 3-5 days; 100 mg/d, 3 times/d for 1-2 weeks thereafter Confirmed: 200-500 mg 3 times/d for 5-7 days	Deficiency promoted by intake of glucose without adequate thiamine. Deficiency can develop in 9-18 days. Associated with refeeding syndrome. Adequate Mg2+ needed for activation. DNI: diuretics increase urinary excretion
Riboflavin (B2)	Angular stomatitis, cheilosis, glossitis, preeclampsia in pregnancy	Malabsorptive disorders, alcohol abuse, malnutrition, pregnancy, vegans	5-30 mg/d in divided doses	Deficiency is very rare. High doses can be used to treat migraines (400 mg/d).
Niacin (B3)	Thickening and rash on sun-exposed skin, dementia, diarrhea, fatigue	Malabsorptive disorders, alcohol abuse, malnutrition	300 mg/d in divided doses for 3-4 weeks	High doses can be used to treat dyslipidemia under medical supervision (500 mg/d to 2,000 mg/d).
Pyridoxine (B6)	Peripheral neuropathy, hyperhomo-cysteinemia, confusion, dermatitis, glossitis, microcytic anemia	Malabsorptive disorders, alcohol abuse, dialysis, eating disorders	50-100 mg/d	High doses can be used to treat nausea and vomiting in pregnancy (10-25 mg/d 3-4 times/d). Can be used to treat neuropathy (1-6 g/d for 12-24 months) but also may not be beneficial. High doses can be neurotoxic and increase the risk for hip fractures in postmenopausal women. DNIs: isoniazid
Folic acid (B9)	Macrocytic anemia, cheilosis, CVD, dementia, hyperhomo-cysteinemia	Alcohol abuse, malabsorptive disorders, prenatal, pregnancy, dialysis	1-5 mg/d Check B12 levels	DNIs: ↓ levels with phenytoin, methotrexate, sulfasalazine, triamterene; ↓ absorption with pancreatic enzymes and metformin
Vitamin B12	Megaloblastic anemia, depression, glossitis, neuropathy, confusion and cognitive decline, hyperhomo-cysteinemia	Malabsorptive disorders, ileostomy, low gastric HCl output, vegans, vegetarians	100-1,000 mcg IM/month; standard MVM for vegans and others	DNIs: proton-pump inhibitors, over-the-counter contraceptives, metformin ↓ B12 absorption
Vitamin C	Scurvy, delayed wound healing, petechiae, corkscrew hairs, bleeding gums; splinter hemorrhages under the nails	Malabsorptive disorders, malnutrition, dialysis	100 mg 3 times/d	Vitamin C assists with iron absorption. DNIs; tetracycline, aspirin, and corticosteroids ↑ urinary excretion
Pantothenic acid (B5)	Peripheral neuropathy, fatigue	Severely malnourished	Not available	Deficiency is extremely rare.
Biotin	Thinning hair, hair loss, periorificial skin rash and fatigue	Severely malnourished	2.5 mg/d for 15 months	Deficiency is extremely rare.
Abbreviations: CVD = cardiovascular disease; d = day; DNI = drug-nutrient interaction; HCl, hydrogen chloride; IM = intramuscular; IV = intravenous; mg = milligram; Mg2+ = magnesium ion; MVM = multivitamin/mineral.

A comprehensive nutrition assessment—including an evaluation of weight history, biochemical data, past and current health status, medications prescribed, and use of dietary supplements, in addition to a diet history—can determine if individuals have or are at risk for developing micronutrient deficiencies.

In addition, a nutrition-focused physical exam should be completed to observe for signs of any micronutrient deficiencies that may be present. Niacin, riboflavin, pantothenic acid, and biotin deficiencies are rare in the United States, although when they do occur, deficiencies of several other micronutrients also tend to be present. This can be seen with certain medications, malabsorption, and alcohol abuse.

Therapeutic doses of the water-soluble vitamins are often used for treating certain medical conditions. For example, riboflavin in high doses has been used to treat migraines, and therapeutic doses of niacin are often used to treat dyslipidemia by increasing high-density lipoprotein cholesterol and reducing triglycerides and low-density lipoprotein cholesterol levels (Table 5.3).^6,7

Fat-Soluble Vitamins

The fat-soluble vitamins include vitamins A, D, E, and K. Each vitamin has unique characteristics that contribute to overall health and wellness. Fat-soluble vitamins have complex absorption because fat must be present in the gastrointestinal tract at the same time as the vitamin for absorption. The fat-soluble vitamins are necessary for immune function, bone health, vision, and blood clotting (see Table 5.4). In contrast to water-soluble vitamins, fat-soluble vitamins can be stored by the body, so deficiencies can take months to become noticeable.

Table 5.4. Summary of the Fat-Soluble Vitamins Form and Function^14-17

Vitamin	Function(s)
Vitamin A: subgroup of retinols; 90% of vitamin A is absorbed; 8% in carotinoids; need fat for absorption of all fat-soluble vitamins	Vision, antioxidant, wound healing
Vitamin D (active form: calcitriol/D3)	Primary role is to maintain serum calcium and phosphorus levels needed to support bone mineralization, neuromuscular functions, calcium absorption, and other cellular functions. Pleiotropic effects*: May reduce risk for cardiovascular disease, promote glucose control and optimal neuromuscular function, reduce the risk for some cancers, reduce the risk for falls, and promote optimal immune function
Vitamin E: comprises 8 naturally occurring compounds: 4 tocopherols and 4 tocotrienols. α-Tocopherol is the most active form; functions as an antioxidant; γ-tocopherol is the most abundant dietary form	Neuroprotective; may reduce the risk for certain cancers due to antioxidant benefits; may reduce serum cholesterol levels
Vitamin K	Involved in the clotting cascade and promotes bone health; synthesized by microbes in the small bowel and colon; vitamin K negates the effects of warfarin (patient education often needed regarding this)
*A pleiotropic effect, in this context, refers to when a nutrient deficiency can affect multiple body systems.

Table 5.5 lists the daily recommendations for intake for adults based on sex and upper tolerable limits. Rich food sources in addition to recommended biomarkers for assessing micronutrient status are also shown.^14-17

Table 5.5. Fat-Soluble Vitamin Recommendations^14-17

Fat-soluble vitamin	RDA/AI: adult men	RDA/AI: adult women	Tolerable Upper Intake Level	Rich food sources	Recommended biomarkers for assessing status
Vitamin A	900 mcg/d	700 mcg/d	3,000 IU/d	Orange and yellow vegetables and fruits, fish, liver, dairy, eggs	Serum retinol, serum retinol–binding protein
Vitamin D	15 mcg/d	19-70 years old: 15 mcg/d >70 years old: 20 mcg/d	100 mcg/d	Orange and yellow vegetables and fruits, fish, liver, dairy, eggs	Serum 25-hydroxyvitamin D
Vitamin E	15 mg/d	15 mg/d	1,000 mg/d	Seeds, nuts, vegetable oils, green leafy vegetables	Serum α-tocopherol
Vitamin K	120 mcg/d	90 mcg/d	ND	Dark leafy greens, broccoli	Serum phylloquinone, prothrombin time
Abbreviations: AI = Adequate Intake; d = day; IU = international unit; mcg = microgram; mg = milligram; ND = not determined; RDA = recommended daily allowance.

Table 5.6 lists common signs and symptoms that may reflect fat-soluble vitamin deficiencies. Other non-nutritional factors can play a role; therefore, it is important for the health-care professional to consider all factors that may be involved and rule out the possibilities, based on clinical status. Table 5.6 also indicates populations at risk and repletion doses to consider when a deficiency has been identified.

Table 5.6. Summary of Clinical Relevance for Fat-Soluble Vitamins^14-17

Vitamin	Signs and symptoms	Conditions that increase risk	Repletion dose	Other notable details
Vitamin A	Night blindness, Bitot spots, poor wound healing, follicular hyperkeratosis	Malabsorptive disorders, poor intake, pregnancy, use of corticosteroids	3,000-15,000 RAE for 10 days	DNIs; ↓ absorption with orlistat, mineral oil, cholestyramine ↑ intake may ↑ hip fracture risk
Vitamin D	Osteomalacia, hypocalcemia, tetany	Malabsorptive disorders, poor intake, liver or renal dysfunction/dialysis, poor sun exposure, obese	50,000 IU/wk for 8 weeks → 1,000 IU/d	DNIs: phenytoin, orlistat, mineral oil ↓ absorption; corticosteroids ↓ levels
Vitamin E	Vision changes, ataxia, hemolytic anemia; deficiency rare	Malabsorptive/GI disorders, intestinal resection, reduced biliary function	200-2,000 mg/d	DNIs: orlistat, mineral oil 800 IU/d may improve NAFLD >400 IU/d may ↑ prostate cancer risk
Vitamin K	Bruising, prolonged bleeding, ↓ bone density	Malabsorptive disorders	Not available but typically 2.5-10 mg twice weekly to daily	DNIs: warfarin; INR goal: 2-3; ↓ absorption with orlistat, mineral oil, cholestyramine Warfarin binds to enteral nutrition tubing; provide more rapid warfarin administration
Abbreviations: d = day; DNI = drug-nutrient interaction; GI = gastrointestinal; INR = international normalized ratio; IU = international unit; mg = milligram; NAFLD = nonalcoholic fatty liver disease; RAE = retinol activity equivalent; wk = week.

Minerals

Similar to vitamins, minerals are classified as elements that are required daily from the diet for health and wellness. Minerals are often organized into 3 categories:

• macrominerals (i.e., calcium, chloride, magnesium, phosphorus, potassium, and sodium)
• trace minerals (i.e., copper, chromium, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc)
• ultra-trace minerals (i.e., arsenic, boron, nickel, silicon, and vanadium)

In contrast to vitamins, the bioavailability of minerals is often poor, which increases the potential for deficiencies.¹⁸ Oxalates, phytates, saponins, and tannins—compounds found in plant-based foods—can interfere with the absorption of calcium, iron, magnesium, and zinc, thereby increasing the potential for deficiencies to develop.

Moreover, excess intake of a particular mineral at 1 time may result in decreased absorption. For example, absorption of calcium is best when consumed in doses of less than 500 mg.¹⁹ When daily doses are needed in greater amounts, the doses should be divided and consumed throughout the day. Table 5.7 reflects the functions as well as other notable details for a selection of minerals.

Table 5.7. Summary of Select Minerals and Function^19-30

Mineral	Functions	Notes
Calcium	Bone and teeth structure; cardiac, neurological, and muscle functions; activation of blood-clotting factors. Higher intakes are associated with lower risk for colon cancer but greater risk for prostate cancer.	The most abundant mineral in the body. The medications classified as aromatase inhibitors (e.g., letrozole, anastrozole, Aromasin [a type of hormone therapy]) prescribed for women with a history of estrogen-positive breast cancer and corticosteroids increase bone loss. Ensure adequate calcium and vitamin D intake.
Iron	Iron is an essential component of hundreds of enzymes and proteins that are necessary for critical functions, such as the production of hemoglobin and myoglobin, which transport oxygen; energy production; and DNA synthesis. Iron is also an active site for many reduction-oxidation enzymes involved in metabolism. Necessary for growth, neurological development, and synthesis of some hormones.	Absorption: Absorption mechanisms differ for heme iron and nonheme iron. Heme iron is absorbed intact into the enterocyte (i.e., red blood cell) after the globin fraction is removed, then hydrolyzed to ferrous iron by the intestinal cell. In the stomach, nonheme iron is released from food, usually in the ferric form, and then converted to ferrous iron via the action of gastric acid. The ferrous iron then binds to receptors primarily in the duodenum and jejunum for absorption.
Magnesium	Essential in the activation of more than 300 enzymatic reactions; required for maintenance of the sodium-potassium-ATPase pump; structural component of bone, neuromuscular transmission, cardiovascular excitability, vasomotor tone, and muscle contraction.	Intake has generally been reported as inadequate for most adults in the United States.
Potassium	Most abundant intracellular cation; needed for sodium-potassium pump and cardiac, muscle, and neurological functions
Sodium	Sodium-potassium pump, fluid/electrolyte balance, and blood pressure	Excess intake increases urinary excretion of calcium.
Zinc	Needed in more than 200 enzymatic reactions; cellular proliferation and differentiation; wound healing; insulin synthesis; glucose control; immune function. Can decrease by 50% of the normal level during the acute phase response* due to zinc sequestration. Consider checking C-reactive protein levels to assess level of inflammation.
Copper	Serves as a cofactor for various enzymatic pathways (commonly referred to as “cuproenzymes”) for energy production, iron metabolism, neurotransmission, and connective tissue synthesis
Iodine	Critical component of thyroid hormones and necessary for overall growth and development
Manganese	Serves as a cofactor for many enzymatic pathways involved in antioxidant defenses, metabolism, bone and cartilage formation, and wound healing	Although manganese deficiencies are extremely rare in humans, neurotoxicity issues can arise in the face of disorders associated with manganese-overload disorders and overconsumption of manganese through inhalation, drinking water, and total parenteral nutrition. Individuals with chronic liver dysfunction are also at a high risk for manganese toxicity.
Selenium	A major constituent for more than 24 selenoproteins that play an essential role in DNA synthesis, thyroid hormone metabolism, reproduction, and antioxidant functions

Ultra-Trace Minerals

The ultra-trace minerals, although needed in very small amounts by the body, play a critical role in maintaining health and wellness. Table 5.8 reflects the daily recommendations for intake, upper tolerable limit, and biomarkers that can be used to assess the status of several ultra-trace elements. Information regarding rich dietary sources is also included.

Chromium, molybdenum, and fluoride are additional trace elements needed for various physiological functions for health. The functions of chromium are not well understood, but chromium plays a role in insulin sensitivity and glucose control. As such, chromium supplementation has been promoted for glucose regulation despite clinical research results being inconclusive.

Molybdenum functions as a cofactor for sulfite oxidase, xanthine oxidase, and aldehyde oxidase. Deficiencies in molybdenum have not been reported in healthy adults but may be present in individuals with very rare metabolic disorders.

Even though fluoride helps prevent tooth decay, it is not considered an essential mineral, because it is not required for growth and survival. However, dental caries are a nutritional concern because poor oral health can cause malnutrition related to difficulty chewing. Furthermore, dental caries can ultimately lead to edentulism (partial or total loss of permanent teeth), which can also lead to inadequate nutrient intake and malnutrition because individuals may be unable to consume a variety of foods.³⁰

Table 5.8. Summary of Daily Reference Values, Food Sources, and Biomarkers for Some Minerals^19-30

Mineral	RDA/AI: men	RDA/AI: women	Tolerable Upper Intake Level	Rich food sources	Biomarkers for assessing status
Calcium	18-70 y.o.: 1,000 mg/d >70 y.o.: 1,200 mg/d	18-51 y.o.: 1,000 mg/d >51 y.o.: 1,200 mg/d	18-50 y.o.: 2,500 mg/d >51 y.o.: 2,000 mg/d	Dairy foods, kale, broccoli, bok choy, fortified foods such as orange juice and cereal	Serum calcium and ionized calcium levels
Iron	>19 y.o.: 8 mg/d	19-50 y.o.: 18 mg/d >51 y.o.: 8 mg/d	45 mg/d	Beef, fortified foods, oysters, white beans	MCV/MCHC, ferritin, serum iron
Magnesium	19-30 y.o.: 400 mg/d >31 y.o.: 420 mg/d	19-30 y.o.: 310 mg/d >31 y.o.: 320 mg/d	350 mg/d*	Pumpkin seeds, chia seeds, almonds, soy milk, beans	Serum magnesium level
Potassium	3,400 mg/d (AI)	2,600 mg/d (AI)	ND	Bananas, potatoes, dairy products, tomatoes, oranges/orange juice	Serum potassium level
Sodium	1,500-2,300 mg/d (AI)	1,500 mg/d-2,300 mg/d (AI)	<2,300 mg/d	Water, processed foods	Serum sodium level
Zinc	11 mg/d	8 mg/d	40 mg/d	Seafood, meats, greens, whole grains	Urinary zinc
Trace minerals
Copper	900 mcg/d	900 mcg/d	2 mg/d	Shellfish, nuts, seeds	Ceruloplasmin
Iodine	150 mcg/d	150 mcg/d	1,100 mcg/d	Iodized salt, seaweed, seafood, eggs, fortified/enriched foods	Urinary iodine levels
Manganese	2.3 mg/d	1.8 mg/d	200-600 mg/d depending on body weight	Nuts, seafood, tea, whole grains	Whole-blood manganese levels
Selenium	70 mcg/d	55 mcg/d	400 mcg/d	Brazil nuts, seafood, organ meats	Plasma or serum selenium levels; hair and nail selenium levels can also be used
Abbreviations: AI = adequate intake; d = day; mcg = microgram; MCHC = mean corpuscular hemoglobin concentration; MCV = mean corpuscular volume; mg = milligram; ND = not determined; y.o. = years old.
*Denotes that the Tolerable Upper Intake Level (UL) is higher than the Recommended Daily Allowance (RDA) for men because the UL reflects recommendations based on using magnesium supplements versus the RDA, which is based on intake from food, beverages, and supplements.

Table 5.9 lists common signs and symptoms that may reflect mineral deficiencies. Because non-nutritional factors can also promote these findings, the health-care professional must discern between nutritional and non-nutritional factors that play a role. Table 5.9 also lists conditions that increase risk for depletion and repletion doses to consider when a deficiency has been identified.

Table 5.9. Mineral Clinical Relevance Summary^19-30

Mineral	Signs and symptoms	Conditions that increase risk	Repletion dose	Other notable details
Calcium	Hypocalcemia can result due to low vitamin D status, CKD, Mg deficiency, rickets and osteoporosis, hypotension, tetany, muscle cramps, seizures	Lactose intolerant/milk allergy, female athletes, postmenopausal, dialysis, vegan diets, malabsorptive disorders	1 g calcium chloride/3 g calcium gluconate	DNIs: bisphosphonates, calcitonin, Lasix, phenytoin
Iron	Microcytic anemia, pica, pallor, fatigue, cheilosis, glossitis, koilonychia, poor pregnancy outcomes	Low gastric acid, malabsorptive disorders, kidney dysfunction, poor intake	150-200 mg/d elemental iron; take with vitamin C	DNIs: PPIs, OC, oral bisphosphonates, phosphate biners, fiber, levothyroxine ↓ absorption
Magnesium	Tetany, Chvostek and Trousseau signs, arrhythmias	Critical illness, malabsorptive disorders, EtOH abuse, AKD/CKD	Laboratory values: 1-1.5 = 2-4 g Mg sulfate; <1 = 4-10 g Mg sulfate	DNIs: platin-based chemotherapy agents, thiazide/loop diuretics ↓ K+/Ca2+ refractory to treatment until Mg levels corrected; ↓ levels with refeeding syndrome
Potassium	Weakness, lethargy, muscle necrosis, arrhythmias	Poor intake, AKD/CKD, malabsorptive disorders, hypermetabolic/refeeding syndrome, diabetes insipidus	Oral: 40-100 mEq/d IV: 10-20 mEq/h depending on severity of ↓ levels	DNIs: diuretics, platin-based chemotherapy agents, insulin
Sodium	Headache, nausea, vomiting, muscle cramps, disorientation	Elderly (deficiency), starvation, PN populations	Based on clinical status	Laboratory values are affected by hydration status
Zinc	Poor wound healing, rash, alopecia, impaired night vision, alterations in taste and smell	Poor intake, alcohol abuse, wound healing/wound drainage, malabsorptive disorders, liver disease and macular degeneration	Wound healing: 220 mg BID for 10 days; macular degeneration: 80 mg/d	DNIs: phosphate binders, fiber ↓ absorption; corticosteroids and propofol ↑ urinary excretion
Copper	Anemia unresponsive to iron supplementation	Neonates fed cow’s milk, malnourished, malabsorptive syndromes, individuals taking high doses of zinc for 6-10 weeks	2-4 mg/d	Deficiency is rare in healthy individuals
Iodine	Goiter, hypothyroidism	Pregnant women who don’t consume dairy products; vegans; individuals not using iodized salt	150-1,100 mcg/d	Pregnant women should take a daily prenatal supplement with 150 mcg
Manganese	Evidence is limited, but deficiency maybe linked to poor growth in children, skin rashes, hair depigmentation, poor bone health	No known populations are at risk	Insufficient data because deficiency is very rare	Deficiency is very rare Individuals with liver dysfunction are at an increased risk for toxicity
Selenium	Keshan disease (cardiomyopathy), Kashin-Beck disease, male infertility, muscular weakness	Malnourished, dialysis, bariatric surgery, GI disorders, and individuals with diet-associated conditions such as PKU	>90 mcg/d	IV selenium may reduce mortality in septic patients in the ICU. High doses (>400 mcg/d) can be toxic.
Abbreviations: AKD = acute kidney disease; BID = twice a day; Ca2+ = calcium; CKD = chronic kidney disease; d = day; DNI = drug-nutrient interaction; EtOH = ethanol; g = gram; GI = gastrointestinal; h = hour; ICU = intensive care unit; IV = intravenous; K+ = potassium; mcg = microgram; mEq = milliequivalent; Mg = magnesium; mg = milligram; OC = oral contraceptive; PKU = phenylketonuria; PN = parenteral nutrition; PPI = proton-pump inhibitor.

Micronutrient Deficiencies

Reportedly affecting more than 2 billion people worldwide, the deficiency of micronutrients has been described as the “hidden hunger”³¹ and can be caused by a multitude of factors. However, because most Americans do not follow the Dietary Guidelines recommendations, poor dietary habits are likely 1 of the primary contributors to inadequate intake.

Worldwide, deficiencies of vitamin A, iron, zinc, folate, and iodine reportedly are the most common.³² Data from the National Health and Nutrition Examination Survey (NHANES) 2005-2016 What We Eat in America survey data noted that in addition to inadequate vitamin A intake (45%), insufficient intakes of vitamins C (46%), D (95%), and E (84%) were also common in the US population when only food intake was evaluated. Inadequate zinc intake was also reported in 15% of the surveyed study participants.³² Although inadequate intake was also described for other micronutrients such as vitamin B₆ (11%), folate (12%), and iron (5%), insufficiencies of these micronutrients are less common.³²

Dietary supplements have led to a reduction in nutrient inadequacy. When the use of dietary supplements was evaluated in addition to food intake, inadequacies were reduced as follows: vitamin A from 45% to 35%; vitamin C, 46% to 33%; vitamin D, 95% to 65%; vitamin E, 84% to 60%; and zinc, 15% to 11%.³²

Check your understanding with the following case study activity:

In addition to the aforementioned variety of factors that can affect micronutrient need and availability, many other factors, such as food choices, food preparation, food plantings and harvesting, and climate change, also have an impact.

Food Choices

“No one size fits all” when it comes to what consumers eat, because there are many reasons why people choose to eat what they do (see chapter 3 for a more in-depth discussion). Popular diets such as low-carbohydrate (low carb), high-protein, or the ketogenic (“keto”) diet (high fat and low carb) are often the focus of “healthy eating.” Moreover, dietary restrictions such as reduced sodium, potassium, or phosphorus may be prescribed based on one’s health status.

Conversely, the national and global dietary recommendations for health and wellness promote a plant-based, whole-foods approach that reflects an intake of a variety of foods that provide not only macronutrients but also important micronutrients and phytonutrients. Examples include the DASH and the Mediterranean diet. Both are evidence-based approaches to preventing and managing diet-related medical conditions.^33,34

These “diets” share similar characteristics in their fundamental principles. Both promote the intake of a variety of fruits, vegetables, unprocessed whole grains, legumes, nuts, seeds, and healthy fats, which provide an array of valuable micronutrients including antioxidants along with phytonutrients. Together, these have a synergistic effect that reduces blood glucose, serum lipid, and inflammatory biomarker levels, thereby promoting disease prevention and management.³⁵ Animal proteins, processed foods, and alcohol are recommended to be consumed less often.

These recommendations contrast with what the average American is reportedly consuming. Most don’t meet the guidelines for fruit and vegetable consumption: only 1 in 10 Americans consumes the recommended servings per day.³² Additionally, most Americans don’t meet the guidelines of 2 to 3 servings per day for dairy intake, although intake of calcium-fortified dairy alternatives can help people meet the RDA for calcium.

Impact of Popular Diets on Micronutrient Intake

In recent years, multiple different eating patterns with distinct attributes have been popularized and followed by American adults. Each dietary pattern may affect micronutrient status. Therefore, understanding the relationship between these diets and micronutrient intake is essential to ensure optimal nutritional and health status. The following discussion reviews selected popular diets, their attributes, and their potential impact on micronutrient excess or deficiency.³⁶ For more information, refer to chapter 8, which reviews popular diets in more detail. Table 5.10 provides a summary of popular diets and their impact on micronutrient status.

Vegetarian-Style Diets

• Lacto-ovo-vegetarian:
  • Attributes: Excludes meat, poultry, and fish but may include dairy (lacto-vegetarian) and egg (ovo-vegetarian) products.
  • Impact on micronutrient status: Lacto-ovo-vegetarians may be at risk for deficiencies in vitamin B₁₂, iron, zinc, and omega-3 fatty acids.
  • Supplementation: Vitamin B₁₂ supplementation is often recommended for vegetarians to meet their needs.
• Vegan diet:
  • Attributes: Excludes all animal products, including meat, fish, eggs, dairy, and honey. Products that may involve animal products or wildlife, such as certain beers or figs, may be excluded too.
  • Impact on micronutrient status: Vegans commonly face potential deficiencies in vitamin B₁₂, iron, calcium, iodine, zinc, and omega-3 fatty acids.
  • Supplementation: Vitamin B₁₂, iron, and omega-3 fatty acid supplementation are often advised for vegans. Calcium and iodine sources should also be carefully considered.

Pescatarian Diet

• • Attributes: Excludes meat and poultry but includes fish and other seafood.
  • Impact on micronutrient status: Pescatarians generally have a lower risk of deficiencies compared with vegetarians because they consume seafood. Seafood provides essential nutrients such as omega-3 fatty acids, vitamin B₁₂, and iron.
  • Supplementation: Depending on individual dietary choices, supplementation may still be necessary, particularly for vitamin D and omega-3 fatty acids.

Paleolithic Diet (Paleo)

• • Attributes: Emphasizes whole foods, lean meats, fish, fruits, vegetables, nuts, and seeds while excluding refined grains, legumes, dairy, and processed foods.
  • Impact on micronutrient status: The paleo diet may result in inadequate intakes of calcium, vitamin D, vitamin E, and some B vitamins.
  • Supplementation: Depending on individual dietary choices and sun exposure for vitamin D synthesis, supplementation may be needed for certain nutrients.

Low-Carbohydrate Diets

• Ketogenic diet (keto)
  • Attributes: High fat, very low carbohydrate, and moderate protein intake; emphasizes intake of nuts and seeds, red meat, poultry, fish and seafood, eggs, full-fat dairy, and oils.
  • Impact on micronutrient status: The keto diet may lead to deficiencies in fiber, vitamin C, vitamin D, vitamin E, vitamin K, calcium, magnesium, potassium, and some B vitamins due to the limited variety of food choices.
  • Supplementation: Supplementation with vitamins and minerals, particularly those mentioned, may be necessary to avoid potential deficiencies.
• Low-carbohydrate/high-protein diet
  • Attributes: Restricts carbohydrate intake while emphasizing high protein consumption.
  • Impact on micronutrient status: Low-carb/high-protein diets may lead to deficiencies in vitamins C, D, and E; folate; calcium; magnesium; and potassium, due to limited intake of fruits, vegetables, and whole grains.
  • Supplementation: Consideration should be given to supplementation, especially for vitamins and minerals commonly found in plant-based foods.

Table 5.10. Summary of Popular Diets Defining Features and Impact on Micronutrient Status³⁶

Vegetarian-style diet	Defining feature	Impact on micronutrient status	Possible supplementation needed
Lacto-ovo-vegetarian	Plant-based foods, excluding meat and fish	Potential deficiency in vitamin B12, iron, zinc, and omega-3 fatty acids	Vitamin B12, iron
Pescatarian	Includes fish, excludes meat and dairy products	Reduced risk of deficiencies compared with vegetarian	Vitamin B12
Vegan	Excludes all animal products	Potential deficiencies in vitamin B12, iron, calcium, and omega-3s	Vitamin B12, iron, calcium, omega-3s
Ketogenic	High fat, very low carbohydrate intake	Possible deficiency in vitamins C, D, E; calcium; and magnesium	B vitamins, vitamins C, D, E; calcium and magnesium
Paleo	Emulates ancestral diets	Potential deficiency in calcium, vitamin D, fiber	Vitamin D and calcium
Low-carb/ high-protein	Low carbohydrate, high protein intake	Potential deficiency in B vitamins and vitamin C	B vitamins and vitamin C

Food Production and Harvesting: How It Affects Micronutrient Availability

The essence of food production depends on the quality of the soil food is grown in as plants extract nutrients from the soil. This makes up the nutrient composition of the plant.

The nutrients obtained from eating chicken, beef, and pork also contribute to a nutrient-dense diet based on the nutrient availability and micronutrient density in these animals’ feeds. Nutrients are returned to the soil through organic matter (plant or livestock biomatter), in addition to the use of inorganic fertilizers. These avenues are essential to maintain or replenish the fertility of the soil. However, the refurbishing of these nutrients rarely fully replaces all that are lost; thus, over time, harvesting results in continued soil nutrient loss. Furthermore, soil nutrient content is variable from region to region throughout the world. Although increased global food production and distribution have reduced some nutritional deficiencies, micronutrient deficiencies related to iron, calcium, zinc, and vitamin A still occur. Lower soil levels of zinc, copper, and manganese have been associated with increased child mortality.³⁷ And micronutrient deficiencies arising from consumption of nutrient-poor foods also can adversely affect childhood and adolescent growth.³⁸

Reportedly, soil degradation affects most of the global food production regions.³⁷ To meet the global need for food in 2050, it is estimated that food production will need to increase by 70% to 100% of today’s production.³⁹ To promote and maintain optimal food production that will produce high nutritional quality food to meet the nutritional needs of the world’s population, including provision of essential micronutrients, soil management is crucial in agriculture. Farming practices that focus solely on increasing yield often lead to lower micronutrient content of the crop.

Global trade of food has led to an increased allocation in the variety of foods available across the world. Although this has led to an increased availability of foods, the availability of nutrient-rich foods may not be equitable. For example, refined wheat products may be fortified with micronutrients lost in processing in some countries, but not all. Fortification typically depends on the economic state of the country. Higher-income countries are more likely to fortify products that have been stripped of their micronutrients.

Increasing global trade of food increases the exposure of the world’s population to foods grown in nutrient-poor soils. Food is highly perishable and prone to damage from pests and nutrient degradation during post-farm production handling, transportation, storage, and packaging. These aggregated factors lead to the consumption of nutrient-poor foods, which can lead to malnutrition and diet-related health consequences.

Farming Practices

Farming practices also play a critical role in the micronutrient content of plants and livestock. Nutrient density is dropping in harvested crops due to over-tilling, use of nitrogen fertilizers, focusing on increased yield, using synthetic pesticides, and other factors. However, implementing regenerative farming practices (replenishing soil organic matter and health), also known as “conservative agriculture,” can result in higher levels of micronutrients and phytonutrients.⁴⁰

Instituting regenerative farming practices improves soil health and plant micronutrient content at farms where traditional practices previously were used. In addition, regenerative farming practices also led to an increase in omega-3 fatty acid levels in meat when compared with meat from grass-fed animals, using conventional farming.⁴⁰

Climate Change

Climate change also can have a significant impact on soil nutrient density. Crops grown in regions with higher carbon dioxide (CO₂) levels reportedly have 3% to 17% less iron, zinc, and protein.⁴¹ Lower protein content in wheat, potatoes, barley, and rice are projected to decline 6% to 14% if atmospheric CO₂ levels continue to increase.⁴² Reduced amounts of several B vitamins, iron, and zinc have been found in different varieties of rice, due to higher levels of CO₂ as well.

Micronutrient Dietary Excesses

Despite popular belief that more is better, excessive intake of several micronutrients may be associated with adverse health outcomes. Food choices such as overconsumption of prepared and fast foods increase sodium intake. Excess fluoride intake during critical periods of tooth formation can be detrimental. Furthermore, increased intake of potassium and phosphorus by patients with chronic kidney disease can increase their risk for morbidity and death. Lastly, dietary supplements are commonly used and contribute, in addition to diet, to the overall intake of micronutrients—something most consumers don’t consider.

The FDA reports adults in the United States consume 3,400 mg of sodium daily, which exceeds the recommendations set forth by the Dietary Guidelines of ≤2,300 mg/d.⁴³ Furthermore, the American Heart Association recommends ≤1,500 mg/d for adults with hypertension. It is concerning, then, that reportedly 40% of US adults, including almost 60% of non-Hispanic Black people, have hypertension related to excessive sodium intake.⁴⁴ Moreover, hypertension may increase the risk for heart disease and stroke, primary causes of death. Processed, packaged, and ready-prepared foods contribute the majority of dietary sodium intake.⁴³ Numerous low-sodium options are available, and their use should be encouraged to reduce intake, in addition to following the DASH or Mediterranean dietary patterns to promote risk reduction.⁴⁵

Beginning in the mid-1940s, a large proportion of the water in the United States has been supplemented with fluoride, based on observations that dental caries were significantly lower in populations drinking water with higher fluoride concentrations. Today, approximately 60% of the US population consumes water from community sources that is fortified with fluoride as a public health measure to reduce the prevalence of dental caries.⁴⁶ Note that bottled water, increasingly consumed by adults, is generally a relatively poor source of fluoride. Although fluoridation of water sources has reduced the prevalence of dental caries in the United States, excess intake of fluoride can lead to dental fluorosis, which occurs when the tooth is developing during the first 8 years of life. Excess fluoride after this time will not have any adverse effects on the teeth.⁴⁶

Using NHANES data from 2011 to 2014, Cowan et al.⁴⁷ found that surveyed participants ≥19 years of age who used dietary supplements exceeded the recommended intake levels for iron, folic acid, vitamin D, and calcium, regardless of their living situations and health status. This, in turn, could lead to adverse outcomes. See chapter 6 for a detailed discussion on dietary supplements.

Several medical conditions, including hemochromatosis and chronic kidney disease, may require restricting micronutrient intake to avoid the adverse effects of overconsumption. For example, in hemochromatosis, iron intake is restricted to prevent excess iron storage in the liver, heart, and pancreas. Excess storage can eventually cause liver, cardiac, and pancreatic failure. Individuals with chronic kidney disease are often counseled to limit their intake of potassium and phosphorus to avoid adverse effects of hyperkalemia and hyperphosphatemia that occur due to compromised renal excretion. Excess intake of vitamin E and calcium also have been linked to an increased risk for prostate cancer in men, with recommendations focused on not exceeding the recommended daily intake levels.⁴⁸

Summary

Although micronutrients are required in small amounts by the body, they are vital for promoting and maintaining health and wellness. Many factors can alter an individual’s micronutrients requirements and status. Dietary choices, health status, availability of and access to healthy foods, and food production methods from farming to processing influence the micronutrient content in the foods we eat and, ultimately, micronutrient status.

By completing a comprehensive nutrition assessment that includes an evaluation of weight history and body composition, available laboratory data, past and present medical status, and dietary habits, individuals with or at risk for developing micronutrient deficiencies can be identified. A nutrition-focused physical exam provides additional data on whether any signs of deficiencies are present.

Subsequently, appropriate counseling can then help prevent deficiencies or maintain or improve micronutrient status. Evaluating current status and risk for deficiency can help prevent or manage medical conditions or diseases associated with various micronutrients.

Consuming plant-based diets such as the DASH or Mediterranean-style diet can provide a rich foundation for micronutrients intakes. These diets also reduce the diet-related diseases of heart disease, stroke, type 2 diabetes, and hypertension. Overall, understanding the factors affecting micronutrient intake can lead to improved, evidenced-based nutrition counseling and intervention.

Practice Case

Andrea is a 23-year-old woman who changed her eating habits 6 months ago because she wanted to become a vegan and heard that the vegan diet was heathier. She’s made an appointment with you because she feels tired and weak often. She also tells you she’s having trouble concentrating, is dizzy at times, and she can feel some tingling in her feet.

You notice her skin looks pale and her tongue is smooth and red.

Diet History

• Breakfast: ½ cup of oatmeal with honey, almonds, and apples. 8 oz of black coffee
• Morning snack: ½ cup of edamame
• Lunch: 1 cup of kale and quinoa salad, lemon vinaigrette dressing; 8 oz of fruit smoothie
• Afternoon snack: handful of pita chips with hummus
• Dinner: lentil soup, small garden salad (mixed greens, olives, vegan feta cheese, and tomatoes), and 2 slices of sourdough bread
• Dessert: fruit sorbet

Patient history: gastrointestinal reflux disease

Medication: proton-pump inhibitor

Laboratory values:

• MCV: 105 femtoliters (fL; normal range: 80-100 fL)
• Hemoglobin: 12.8 g/dL (normal range: 14-18 g/dL)

Using the information about Andrea in the preceding practice case, test your understanding by answering the questions in the following activities:

 

References

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