Minerals

Three broad functions/roles of minerals.

1. cofactors/catalysts

2. facilitate specific structures and metabolic functions

3. cellular signaling processes

What are the five minerals of concern?

1. calcium (major)

2. potassium (major)

3. sodium (major)

4. iron (trace)

5. zinc (trace)

What has led to the underconsumption of some nutrients and dietary components such as calcium, potassium, dietary fiber, and vitamin D?

inadequate intake of nutrient dense foods and beverages

In general, what was the 2025 DGA recommendation for diets in American households?

• prioritize diets build on whole, nutrient dense foods (protein, dairy, vegetables, fruits, healthy fats, and whole grains

• reduction in highly processed foods (refined carbs, added sugars, excess sodium, unhealthy fats, and chemical additives

What are the different mineral concerns for each life stage? (infancy/early childhood, adolescence, young adulthood, pregnancy)

• infancy and early childhood: iron

• adolescence: calcium and iron

• young adulthood: iron

• pregnancy: iron, calcium, and iodine

What are minerals of concern for vegetarian and vegan diets?

• vegetarian: iron

• vegan diets: calcium, iron, magnesium, and zinc

What is the recommended sodium intake?

< 2300 mg/day

• even less for children younger than 14 years

• highly active individuals may benefit from increased sodium intake

Functions of calcium (4).

1. bone mineralization/bone health/prevent osteoporosis

2. cell signaling

3. blood clotting

4. nerve transmission

What percent of women and men ages 19+ dont consume enough calcium?

• men: 30%

• women: 60%

When is adequate intake of Ca and Vit. D essential?

• 19-30 years: peak bone mass formation

• post-menopausal: bone remodeling

What are good calcium sources?

• dairy (provide over half of Ca in US)

• certain vegetables and grains

What does Ca increase the absorption of?

food sources of Ca increases Zn absorption from mixed and plant based diets (matrix effect)

• supplements with carbonate reduces Zn absorption

What molecules inhibit the bioavailability of Ca (2)? Where can these molecules be found?

1. oxalic acid (oxalates): spinach

2. phytic acid (phytates): raw beans

When are Ca supplements most primal?

• best absorbed when taken in doses < 500mg

  • similar efficiency as milk

What are good biomarkers that are used as an indicator of Ca status (2)?

• bone mineral density (measured by DEXA)

• Ca retention (balance studies measure bone accretion an Ca excretion)

What are two biomarkers that are not that great of an indicator of Ca status?

1. serum Ca concentrations (too tightly regulated)

2. Ca intake and fracture risk prospective studies (hard bc fractures rarely occur)

What happens to children’s bone with low calcium intake?

• poor bone mineralization

• bones become soft and pliable (bowing of legs)

• will grow in length but not in strength

What happens to adults with low calcium intake?

1. osteomalacia

2. osteoporosis

What is osteomalacia?

• demineralization of bone due to loss of Ca and phosphorus crystals

• can occur with poor Ca or Vit D

What is osteoporosis?

loss of total amount of bone

B

What is the DRI for calcium in mg/day?

Average intake of sodium in US

> 3 g/day

How is most sodium consumed in US?

comes from salt added during commercial processing and preparation

What is the issue with high sodium intake?

increases CVD risk factors

• hypertension (>140/90mm Hg)

• hyperlipidemia (high LDL cholesterol)

• low HDL cholesterol (<40 mg/dl)

• cigarette smoking

• diabetes

• physical inactivity

• antherogenic diet (dietary pattern that promotes atherosclerosis)

What are five strategies for reducing sodium intake?

1. read the Nutrition Facts label

2. prepare your own food when you can

3. add flavor without adding sodium

4. buy fresh

5. watch your veggies

6. give sodium the rinse (rinse sodium containing canned foods before eating)

7. unsalt your snacks (choose low sodium)

8. consider your condiments (add oil/vinegar to salads rather than dressing)

9. reduce your portion sizes

10. make lower sodium choices at restaurants (ask for meal without salt, or ask for dressings/sauces on the side)

What do nutrient claims surrounding sodium mean?

Three benefits of reduced sodium intake.

1. fewer strokes

2. fewer CVD events and deaths

3. health care savings

What ist he DASH diet?

a heart-healthy eating plan designed to lower or prevent high blood pressure

• DASH = dietary approaches to stop hypertension

• balanced eating plan that helps create a heart healthy eating style for life

• emphasizes vegetables, fruits, and whole grains

• include fat free/low fat dairy products

• fish, poultry, beans, nuts, and vegetable oils

• limit saturated fat

• limit sugar sweetened beverages and sweets

• adequate Ca, K, and Mg

D

Four benefits of DASH diet?

1. based on findings from research studies

2. tested dietary pattern rather than single nutrients

3. lowers BP

4. lowers LDL cholesterol

What dietary pattern aligns the best with the American Heart Association 2021 Dietary guidance?

DASH diet

Two roles of potassium.

1. main intracellular cation in the body

2. required for normal cellular function

Foods rich in potassium.

• raisins/prunes

What is the AI of potassium based off of?

• based on level of dietary intake to maintain lower blood pressure, reduced risk of recurrent kidney stones, and possibly decrease bone loss

What is the UL of potassium?

no UL, excess above AI is excreted in urine

Potassium DRIs.

• newer ones separate by sex

• older DRIs recommend higher intake, but afterwards, the values are lower

What are some characteristics surrounding potassium deficiency (hypokalemia)?

• uncommon

• cardiac arrhythmia, muscle weakness and glucose intolerance

• moderate potassium deficiency: elevated BP, increased salt sensitivity, increased risk of kidney stones, increased bone turnover, and increased CVD

Two functions of iron.

1. metabolic/enzymatic functions

2. transport and utilize oxygen

Four places iron can be found.

1. hemoglobin

2. myoglobin

3. cytochromes

4. iron sulfur proteins

What is the storage form of iron? Why do we have it?

ferritin

• helps with the maintenance of iron homeostasis

• has to be bound in blood, otherwise it can be toxic and cause free radicals

What increased consumption of this thing could lead to anemia?

increased milk consumption

• dairy products are low in iron

Describe the relationship between supplemental calcium and iron/zinc.

supplemental calcium may decrease iron and zinc absorption

Describe the relationship between iron and vitamin C.

vitamin C helps body to absorb iron

• recommended to eat together

What factors do you need to take into account when using a factorial modeling method for estimating iron requirement.

• basal iron losses

• menstrual losses

• accretion

• storage

  • would sum up all the factors to estimate the amount of iron needed to be absorbed from diet

  • statistical approaches are used to determine population distribution of these components, determine EAR and RDA

What are the EAR, RDA, and AI for iron in mg/day?

What factors are considered when making the AI for iron during infancy 0-6 months?

• assumes young infants will use iron stores to meet need at first 6 months

What factors are considered when making the EAR/RDA for iron 7month + and children ?

• takes into account (factorial method)

  • obligatory (basal) losses through fecal, urinary, and dermal

  • increased HgB mass

  • increase in tissue (non-storage) iron

  • increase in storage iron

How do iron needs differ during pregnancy and lactation? Why?

• pregnancy: needs increase (27mg vs 18mg pre-pregnancy bc wants to create iron stores in baby + development)

• lactating: needs decrease before menstruation returns (9-10 mg)

How prevalent is iron deficiency amongst pregnant and lactating women?

• pregnant women: 1 in 10

  • third trimester: 1 in 4

What are three general dietary sources of iron?

1. heme-iron (animal sources)

2. non-heme iron (plant and animal sources)

3. lactoferrin (human milk)

Examples of iron rich baby foods.

• fortified foods such as cherrios are good too (especially as a weaning food)

EAR of iron.

~15 micrograms/L (serum ferritin concentration)

Describe the difference between the absorption of heme and nonheme iron in the GI tract system.

• heme:

  • double the absorption

  • can get into tissue more efficiently

• non-heme:

  • 3+ needs to be reduced to 2+ to be absorbed through DMT1 into the enterocyte

  • vitamin C reduces 3+ to 2+

What are functional indicators of iron deficiency?

1. reduced work capacity

2. delayed psychomotor development

3. impaired cognitive function

4. adverse maternal and fetal outcomes

5. microcytic anemia

6. iron deficiency anemia

What is the UL of iron?

45 mg/day

• based on GI distress symptoms from iron supplements

Characteristics of excessive iron intake.

• GI distress

• impaired zinc absorption

• CVD (due to oxidative stress)

• Cancer (DNA strand breaks)

Five functions of zinc.

1. optimal growth and development

2. needed for protein structure (zinc fingers) and regulation of gene expression

3. needed for intracellular and extracellular signaling

4. in several reactions in metabolism of proteins, carbs, and fat

5. cofactor for >200 known enzyme (structural or cofactor roles in 10% of human proteome)

What are seven symptoms of zinc deficiency?

1. stunting

2. reduced immune function

3. increased susceptibility to GI infections

4. reduced glycemic control (non-communicable disease risk)

5. rash/reduced wound healing

6. loss of taste

7. reduced reproductive performance

What are some zinc food sources?

• typically found with dietary proteins

  • poultry, meats (high in terms of commonly eaten food)

  • seafood (oysters, highest content)

  • germ and bran (need to remove phytate)

  • fortified breakfast cereals

  • seeds and nuts

What are some nutritional factors that affect Zn absorption?

1. phytate (storage form of phosphorus from plants): decrease absorption

2. protein: increase

3. supplement based iron interactions: decrease (competitive absorption)

   1. if added with protein then it doesn’t really impact it

4. Ca interaction (depends on source)

5. fiber: decrease (so much that it decreases gut transit time, Zn moves too quickly and thus reduces absorption)

Zn AI for infants 0-6 months.

AI = 2 mg/day

• based on human milk

What factors are considered when determining the minimum average amount of dietary zinc for adults and children?

• based on the balance between absorption and endogenous loss (factorial approach)

What is a simplified model?

model that does not make recommendations based on differences in bioavailability

What is effect of excessive zinc intake?

• no evidence of adverse effects from food sources

• immune suppression at high doses > 300 mg/day

  • acute: GI distress, nausea, loss of appetite

  • chronic: reduced copper status, reduced iron incorporation into hemoglobin

UL of Zn.

40 mg/day

• from supplements

• reduced activity of erythrocyte Cu/Zn superoxide dimutase (SOD1) activity