Micronutrients

Vitamins, minerals, and what you actually need.

Why Micronutrients Matter

Unlike macros (protein, carbs, fat), micronutrients are needed in smaller amounts but are equally essential:

• Energy production: B vitamins, iron, magnesium
• Immune function: Vitamins A, C, D, zinc
• Bone health: Calcium, vitamin D, vitamin K
• Antioxidant protection: Vitamins C, E, selenium
• Hormone production: Zinc, vitamin D, magnesium
• Nervous system: B vitamins, magnesium

The good news: If you eat a varied diet of whole foods, you likely get most of what you need.

Vitamins

Fat-Soluble Vitamins

Stored in body fat, so you don't need daily intake. Can accumulate to toxic levels.

Vitamin A (Retinol)

Functions:

• Vision (especially night vision)
• Immune system
• Skin health
• Cell growth

Deficiency symptoms:

• Night blindness
• Dry skin
• Frequent infections

Sources:

• Animal (retinol): Liver, eggs, dairy, fish
• Plant (beta-carotene): Carrots, sweet potatoes, spinach, kale

RDA: 900 mcg (men), 700 mcg (women)

Upper limit: 3,000 mcg (from supplements)

Note: Plant sources (beta-carotene) are converted to active vitamin A, but inefficiently. Animal sources are superior.

Vitamin D (Calciferol)

Functions:

• Calcium absorption (bone health)
• Immune system
• Mood regulation
• Testosterone production
• Muscle function

Deficiency symptoms:

• Weakened bones
• Frequent illness
• Fatigue
• Depression
• Muscle weakness

Sources:

• Sun exposure: 15-30 min midday (most effective)
• Fish (salmon, mackerel, sardines)
• Egg yolks
• Fortified dairy

RDA: 600 IU (often insufficient)

Optimal levels: 30-50 ng/mL blood serum

Supplementation: 1,000-4,000 IU daily for most people in winter or without sun exposure

Get tested: Check 25-hydroxyvitamin D levels annually

Vitamin E (Tocopherol)

Functions:

• Antioxidant
• Cell membrane protection
• Immune function
• Skin health

Deficiency symptoms:

• Rare in healthy people
• Muscle weakness
• Vision problems

Sources:

• Nuts and seeds
• Vegetable oils
• Avocado
• Spinach

RDA: 15 mg

Note: Easy to get from whole foods. Supplementation not usually necessary.

Vitamin K

Functions:

• Blood clotting
• Bone metabolism
• Cardiovascular health

Two forms:

• K1 (phylloquinone): From plants, clotting
• K2 (menaquinone): From animals/fermented foods, bone and heart health

Deficiency symptoms:

• Easy bruising
• Excessive bleeding

Sources:

• K1: Leafy greens (kale, spinach), broccoli
• K2: Natto, grass-fed dairy, egg yolks, liver

RDA: 120 mcg (men), 90 mcg (women)

Note: K2 is more important and harder to get. Consider supplementation if not eating liver or natto.

Water-Soluble Vitamins

Not stored in body, excess excreted. Need regular intake.

Vitamin C (Ascorbic Acid)

Functions:

• Collagen synthesis
• Antioxidant
• Immune support
• Iron absorption
• Wound healing

Deficiency symptoms:

• Scurvy (rare)
• Slow wound healing
• Frequent infections
• Fatigue

Sources:

• Citrus fruits
• Bell peppers
• Broccoli
• Brussels sprouts
• Strawberries
• Kiwi

RDA: 90 mg (men), 75 mg (women)

Higher needs: Smokers, athletes, stress

Supplementation: 200-500 mg if not eating fruits/vegetables daily

B-Complex Vitamins

The B vitamins work together for energy metabolism.

Special notes:

B12: Only in animal foods. Vegans must supplement (1,000 mcg daily or 2,000 mcg weekly).

Folate: Critical for pregnancy (prevents neural tube defects). Women of childbearing age: 400-800 mcg daily.

B6: Needs increase with protein intake.

B-Complex supplement: Good insurance if stressed, active, or dieting.

Minerals

Macrominerals

Needed in larger amounts (>100 mg/day).

Calcium

Functions:

• Bone and teeth structure
• Muscle contraction
• Nerve signaling
• Blood clotting

Deficiency symptoms:

• Osteoporosis
• Muscle cramps
• Numbness

Sources:

• Dairy (milk, yogurt, cheese)
• Leafy greens
• Sardines (with bones)
• Fortified plant milks
• Tofu (calcium-set)

RDA: 1,000 mg (adults), 1,200 mg (50+)

Absorption: Needs vitamin D. Spread intake throughout day.

Supplementation: If not eating dairy or fortified foods regularly.

Magnesium

Functions:

• 300+ enzymatic reactions
• Muscle and nerve function
• Blood pressure regulation
• Sleep quality
• Energy production

Deficiency symptoms:

• Very common (50% of people)
• Muscle cramps
• Poor sleep
• Fatigue
• Anxiety

Sources:

• Dark leafy greens
• Nuts and seeds
• Dark chocolate
• Avocado
• Legumes
• Whole grains

RDA: 400-420 mg (men), 310-320 mg (women)

Supplementation: 200-400 mg highly recommended. Magnesium glycinate or citrate. Take before bed for sleep benefits.

Potassium

Functions:

• Fluid balance
• Blood pressure regulation
• Muscle contraction
• Nerve signals

Deficiency symptoms:

• Muscle weakness
• Fatigue
• Cramps
• High blood pressure

Sources:

• Potatoes
• Bananas
• Beans
• Leafy greens
• Fish
• Avocado

RDA: 3,400 mg (men), 2,600 mg (women)

Note: Most people don't get enough. Eat more whole foods, especially potatoes and leafy greens.

Sodium

Functions:

• Fluid balance
• Nerve signaling
• Muscle contraction

Deficiency symptoms:

• Rare in modern diet
• Low blood pressure
• Hyponatremia (endurance athletes)

Sources:

• Table salt
• Processed foods
• Added to meals

Recommendation:

• General population: 2,300 mg max
• Athletes/active: 3,000-5,000 mg often appropriate
• Low-carb dieters: Need more (keto flush)

Reality: Unless you have hypertension, salt isn't the villain. Processed foods are.

Phosphorus

Functions:

• Bone health
• Energy metabolism (ATP)

Sources:

• Meat, fish, dairy
• Nuts, legumes

RDA: 700 mg

Note: Deficiency rare. Widespread in foods.

Trace Minerals

Needed in smaller amounts (<100 mg/day).

Iron

Functions:

• Oxygen transport (hemoglobin)
• Energy production
• Immune function

Two types:

• Heme iron (animal): Well-absorbed (15-35%)
• Non-heme iron (plant): Poorly absorbed (2-20%)

Deficiency symptoms:

• Fatigue
• Weakness
• Pale skin
• Shortness of breath
• Cold hands/feet

Sources:

• Animal: Red meat, liver, oysters
• Plant: Spinach, lentils, fortified cereals

RDA: 8 mg (men), 18 mg (women), 27 mg (pregnant)

Special considerations:

• Women of childbearing age at higher risk
• Vegetarians need 1.8x the RDA
• Vitamin C enhances absorption

Testing: Check ferritin levels if fatigued. Target 30-50 ng/mL minimum.

Supplementation: Only if deficient. Too much iron is harmful.

Zinc

Functions:

• Immune function
• Testosterone production
• Wound healing
• Protein synthesis
• Sense of taste and smell

Deficiency symptoms:

• Weak immune system
• Hair loss
• Loss of appetite
• Impaired taste
• Low testosterone

Sources:

• Oysters (highest)
• Red meat
• Poultry
• Shellfish
• Legumes (lower absorption)
• Pumpkin seeds

RDA: 11 mg (men), 8 mg (women)

Absorption: Competes with copper and iron. Plant sources less bioavailable.

Supplementation: 15-30 mg if not eating much meat. Don't exceed 40 mg.

Selenium

Functions:

• Antioxidant
• Thyroid hormone metabolism
• Immune function

Deficiency symptoms:

• Rare in developed countries
• Weakened immune system
• Thyroid issues

Sources:

• Brazil nuts (1-2 nuts = daily needs)
• Fish
• Meat
• Eggs

RDA: 55 mcg

Upper limit: 400 mcg

Easy win: Eat 1-2 Brazil nuts daily.

Iodine

Functions:

• Thyroid hormone production
• Metabolism regulation

Deficiency symptoms:

• Goiter
• Hypothyroidism
• Fatigue
• Weight gain

Sources:

• Iodized salt
• Seaweed
• Fish
• Dairy

RDA: 150 mcg

Note: If not using iodized salt or eating fish, consider supplement.

Copper

Functions:

• Red blood cell formation
• Nerve function
• Immune system

Sources:

• Shellfish
• Nuts
• Seeds
• Organ meats

RDA: 900 mcg

Note: Balance with zinc (10:1 ratio, zinc:copper).

Food First Approach

Best Micronutrient-Dense Foods

Simple Micronutrient Strategy

Daily habits:

1. Eat 1-2 servings colorful vegetables
2. Eat 1-2 servings leafy greens
3. Eat quality protein sources (meat, fish, eggs)
4. Include variety: Don't eat the same foods every day

Result: You'll hit most micronutrient needs.

When to Supplement

High-Priority Supplements

Consider supplementing if you can't get enough from food:

Medium-Priority Supplements

Helpful but not critical:

Low-Priority Supplements

Usually unnecessary if eating well:

• Vitamin E
• Most antioxidants
• "Greens" powders (expensive vegetables)
• Exotic supplements

Testing Your Levels

Worth testing periodically:

How: Ask your doctor or use at-home testing services.

Common Deficiencies

Most Common in General Population

1. Vitamin D: 40% of Americans
2. Magnesium: ~50% insufficient
3. Vitamin B12: 15% (higher in vegetarians/vegans)
4. Iron: 20% of women
5. Iodine: Increasing as fewer people use iodized salt

Most Common in Specific Groups

Vegetarians/Vegans:

• B12 (must supplement)
• Iron (need 1.8x RDA)
• Zinc (lower absorption from plants)
• Omega-3 EPA/DHA (consider algae supplement)

Athletes:

• Magnesium (increased losses)
• Vitamin D (if training indoors)
• Iron (women especially)
• Sodium (endurance athletes)

Low-carb/Keto:

• Magnesium (electrolyte losses)
• Sodium (need more)
• Potassium (important to supplement)

Practical Application

The Micronutrient Checklist

Hit these daily for solid nutrition:

• [ ] 1-2 servings leafy greens
• [ ] 1-2 servings other colorful vegetables
• [ ] 1-2 servings fruit
• [ ] Quality protein source (meat, fish, eggs)
• [ ] Nuts or seeds (small handful)
• [ ] Fatty fish or omega-3 supplement (2-3x/week)
• [ ] 15-30 min sun exposure OR vitamin D supplement
• [ ] Magnesium supplement before bed

Sample Day of Micronutrient-Dense Eating

Breakfast: 3 eggs (B12, D, choline) + spinach (K, folate, magnesium) + berries (C, antioxidants)

Lunch: Salmon (D, B12, omega-3s) + sweet potato (A, C, potassium) + broccoli (C, K, folate)

Snack: Greek yogurt (B12, calcium) + 1-2 Brazil nuts (selenium) + pumpkin seeds (zinc, magnesium)

Dinner: Grass-fed beef (B12, iron, zinc) + mixed salad (A, K, C) + avocado (magnesium, potassium)

Supplement: Vitamin D (2,000 IU) + Magnesium (300 mg) before bed

Result: Hit virtually all micronutrient needs.

Key Takeaways

1. Food first: Eat a variety of whole foods
2. Color matters: More colors = more nutrients
3. Don't fear animal foods: Most bioavailable sources
4. Supplement strategically: D, magnesium, omega-3s are smart
5. Test don't guess: Check vitamin D and iron if concerned
6. Consistency wins: Good nutrition daily beats perfection sporadically