Nutritional Deficiency and Disease

1. Nutrient Deficiency

Nutrient deficiencies or diseases can be the result of poor nutritional intake, chronic health conditions, acute health conditions, medications, altered nutrient metabolism, or a combination of these factors, and can impact the levels of both macronutrients and micronutrients in the body. Deficiencies of nutrients can lead to alterations in energy metabolism, immune function, cognitive function, bone formation, and/or muscle function, as well as growth and development if the deficiency is present during fetal development and early childhood.

did you know

The Centers for Disease Control and Prevention (CDC) estimated that less than 10% of the United States population has nutrient deficiencies; however, nutrient deficiencies vary by age, gender, and/or race, and ethnicity.

Intake patterns of individuals can lead to nutrient inadequacy or nutrient deficiencies among the general population. Intakes of nutrients that are routinely below the Dietary Reference Intakes (DRI) can lead to a decrease in how much of the nutrient is stored in the body and how much is available for biological functions. DRIs are based on age and sex and include Recommended Dietary Allowance (RDA), Adequate Intake (AI), Estimated Average Requirement (EAR), and Tolerable Upper Intake Level (UL).

key concept

DRIs are established by the National Academies of Science, Engineering and Medicine and include the following definitions:

• RDA - Indicates the average daily intake of particular nutrients to meet the requirements of 97-98% of healthy people.
• AI - Established to assume adequate intake when there is insufficient evidence to develop an RDA.
• EAR - The average daily intake of a nutrient that is thought to meet the needs of 50% of healthy individuals. EARs are used to assess the adequacy of nutrient intakes among populations rather than the individual.
• UL - The highest nutrient intake that is considered to be safe and does not lead to adverse health effects in the general population.

2. Nutrient Diseases

Macronutrient deficiencies include deficiencies in protein, fat, and/or calories, and can lead to stunting, wasting (marasmus) or a disproportionately large abdomen (a sign of kwashiorkor). Marasmus is a disease of severe wasting due to a prolonged inadequate intake of protein, carbohydrate, and fat. Kwashiorkor is a disease that results from a prolonged inadequate intake of protein.

Essential fatty acid deficiencies, which would include omega-3 fatty acid deficiency, are thought to be rare among the general population. Signs of an essential fatty acid deficiency may include a dry scaly rash, decreased growth in infants and children, lowered immune response, and impaired wound healing.

Micronutrient deficiencies would include deficiencies in vitamins and minerals in the body. According to National Health and Nutrition Examination Survey (NHANES) data, the most common nutrient deficiencies in the general United States population are vitamin B6, iron, vitamin D, vitamin C, and vitamin B12. Because NHANES does not assess the status of all vitamins and minerals, there may be other micronutrient deficiencies that are present in the population without an estimated prevalence.

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Micronutrient deficiencies during pregnancy are not only a concern for the mother, but are of great concern to the developing fetus that is at risk of certain birth defects related to inadequate levels of certain nutrients including B vitamins, vitamin K, magnesium, copper, and zinc. Iodine deficiency during pregnancy can lead to irreversible adverse effects on fetal growth and development. Iodine deficiency is the leading cause of intellectual disability worldwide. Because intake patterns of pregnant women can exclude or limit specific food groups, it is not uncommon to have multiple nutrient deficiencies during pregnancy. For example, iron deficiency usually does not occur alone, but it often occurs in conjunction with other vitamin and mineral deficiencies.

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Some of the most common deficiencies are calcium, vitamin D, iron, vitamin b12, and folate.

terms to know

Macronutrient Deficiencies

Deficiencies in protein, fat, and/or calories, and can lead to stunting, wasting (marasmus) or a disproportionately large abdomen.

Marasmus

A disease of severe wasting due to a prolonged inadequate intake of protein, carbohydrate, and fat.

Kwashiorkor

A disease that results from a prolonged inadequate intake of protein.

Essential Fatty Acid Deficiencies

Omega-3 fatty acid deficiency. Signs may include a dry scaly rash, decreased growth in infants and children, lowered immune response, and impaired wound healing.

Micronutrient Deficiencies

Deficiencies in vitamins and minerals in the body.

2a. Calcium Deficiency

Calcium is a mineral that helps us build and maintain strong bones and teeth as well as conducting muscle and nerve impulses. Short-term indications of calcium deficiency are rare because it is stored in our bones, and our body can take the stored calcium and put it into our blood if needed. Milk, yogurt, and cheese are rich natural sources of calcium. In the United States, approximately 72% of calcium intakes come from dairy products and foods with added dairy ingredients.

Calcium deficiency can reduce bone strength and lead to osteoporosis, which is characterized by fragile bones and an increased risk of falling. Another effect of chronic calcium deficiency is osteomalacia, or defective bone mineralization and bone softening, which can occur in adults and children. Calcium deficiency (or even lower levels of intake) can negatively impact bone health in children and adults, increase risks for certain types of cancer, increase risks for cardiovascular disease, make weight management more difficult, increase risks for preeclampsia, and enhance the effects of metabolic syndrome. A substantial proportion of people in the United States consume less than recommended amounts of calcium. Those at highest risk for inadequate calcium intake are non-Hispanic whites, Hispanics, and those living in poverty.

2b. Vitamin D Deficiency

Vitamin D (also referred to as “calciferol”) is a fat-soluble vitamin that is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced in our bodies when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D promotes calcium absorption and like calcium, is needed for bone growth and maintenance.

Without enough vitamin D, bones can become brittle and misshapen (in the case of rickets). Most people in the US do not get enough vitamin D, and this is especially important for children who may suffer from skeletal deformities, dental deformities, and developmental delays without appropriate levels. Vitamin D at adequate levels can prevent osteoporosis and osteomalacia (when paired with calcium), reduce risk of certain cancers, decrease risk of cardiovascular disease, reduce risk of contracting multiple sclerosis, improve mood and reduce depression, and improve outcomes from type 2 diabetes as well as weight loss.

2c. Iron Deficiency

Iron is a mineral that is naturally present in many foods, added to some food products, and available as a dietary supplement. Iron is an essential component of hemoglobin, an erythrocyte (red blood cell) protein that transfers oxygen from the lungs to the tissues. Iron deficiency is not uncommon in the United States, especially among young children, women of reproductive age, and pregnant women, people with cancer, heart failure, and gastrointestinal disorders or bleeding. Because iron deficiency is associated with poor diet, malabsorptive disorders, and blood loss, people with iron deficiency usually have other nutrient deficiencies.

2d. Vitamin B12 Deficiency

Vitamin B12 is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement and a prescription medication. Causes of vitamin B12 deficiency include difficulty absorbing vitamin B12 from food, lack of intrinsic factor (e.g., because of pernicious anemia), surgery in the gastrointestinal tract, prolonged use of certain medications (e.g., metformin or proton pump inhibitors, discussed in more detail below in the section on interactions with medications), and dietary deficiency. In pregnant and breastfeeding women, vitamin B12 deficiency might cause neural tube defects, developmental delays, failure to thrive, and anemia in offspring. Adequate levels of vitamin B12 may help prevent cardiovascular disease and stroke, decrease risks for certain cancers, delay onset of dementia and other cognitive disorders, and enhance athletic performance.

2e. Folate Deficiency

Folate is a water-soluble B vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Although most people consume adequate amounts of folate, certain groups, including women of childbearing age and non-Hispanic black women, are at risk of insufficient folate intakes. Folate deficiency usually coexists with other nutrient deficiencies because of its strong association with poor diet, alcoholism, and malabsorptive disorders. Megaloblastic anemia, which is characterized by large red blood cells, is the primary clinical sign of folate or vitamin B12 deficiency. Its symptoms include weakness, fatigue, difficulty concentrating, irritability, headache, heart palpitations, and shortness of breath. Adequate folate intake may decrease the risk of having a child with autism spectrum disorder, reduce risk of some cancers, decrease risk for cardiovascular disease, prevent dementia and declines in cognitive function, reduce rates of depression, decrease chances of preterm birth, congenital heart defects, and other congenital abnormalities.

3. Who is at Risk for Nutrient Deficiencies or Diseases?

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Populations who may be at greater risk of nutrient deficiencies or diseases include the following:

• Individuals who have intakes below the established RDA, AI, or EAR for the nutrient.
• Individuals who experience low or very low food security.
• Individuals who are experiencing homelessness.
• Women who have a short interpregnancy interval.
• Individuals who have recently left their previous country of residence.
• People with a gastrointestinal disease that can limit absorption of nutrients (i.e., celiac disease or Crohn’s disease) or individuals with a history of gastrointestinal surgery (including gastric bypass). For example, individuals who have had a portion of their stomach removed or their distal ileum removed during a weight-loss or other surgery are at a greater risk of developing a vitamin B12 deficiency.
• Individuals with other medical conditions that influence nutrient status (i.e., cystic fibrosis, renal disease, genetic disorders).
• Individuals on medications that are known to interact with the absorption or excretion of certain vitamins and minerals.
• People with substance use disorders (including alcohol) may be more likely to have deficiencies due to poor intake and/or the effects of the substance. People who have high intakes of alcohol are at greater risk of developing a magnesium deficiency.
• People who smoke are more likely to have a vitamin C deficiency due to the increase in oxidative stress.

Nutrient deficiencies or diseases can be subclinical or clinical. Subclinical deficiencies involve changes to the concentrations of the micronutrient in the blood or tissues. Clinical deficiencies involve noticeable changes to the appearance of skin, nails, hair, oral cavity, and bone formation as well as major disturbances in the function of cells and tissues in the body. At either stage of a nutrient deficiency, blood work is often taken to confirm a deficiency. Blood work to detect nutrient deficiencies can be misleading, as some nutrients, such as magnesium, may have an overall deficiency in the body but be at a normal level in the blood. Other methods can be used to assess for nutrient deficiency disease, such as a physical nutrition assessment.

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For individuals who currently have a nutrient deficiency or disease, nutrition professionals can:

• Encourage improved intake of whole grains, legumes, dairy, lean protein, fruits, and vegetables.
• Emphasize appropriate portion size and variety to avoid nutrient to nutrient interaction. (For example, excessive calcium intake inhibits the absorption of iron.)
• Provide education on foods that contain the specific nutrient(s) of concern.
• Provide education on preparing foods that are available and will address the deficiency.
• Refer individuals who report low or very low food security to appropriate resources in the community like the Supplemental Nutrition Assistance Program (SNAP) and/or food pantries.
• Refer individuals to healthcare professionals for medical care.

terms to know

Subclinical Deficiencies

Changes to the concentrations of the micronutrient in the blood or tissues.

Clinical Deficiencies

Noticeable changes to the appearance of skin, nails, hair, oral cavity, and bone formation as well as major disturbances in the function of cells and tissues in the body.

REFERENCES

U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - vitamin D. NIH Office of Dietary Supplements. Retrieved July 24, 2022, from ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - calcium. NIH Office of Dietary Supplements. Retrieved July 24, 2022, from ods.od.nih.gov/factsheets/Calcium-HealthProfessional/

U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - iron. NIH Office of Dietary Supplements. Retrieved July 24, 2022, from ods.od.nih.gov/factsheets/Iron-HealthProfessional/

U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - vitamin B12. NIH Office of Dietary Supplements. Retrieved July 24, 2022, from ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/

U.S. Department of Health and Human Services. (n.d.). Office of dietary supplements - folate. NIH Office of Dietary Supplements. Retrieved July 24, 2022, from ods.od.nih.gov/factsheets/Folate-HealthProfessional/

341 nutrient deficiency or disease.6 - Missouri. (n.d.). Retrieved July 24, 2022, from health.mo.gov/living/families/wic/localagency/wom/pdf/341-definition.pdf