Essential Micronutrients Guide

Vitamin D

Vitamin D functions both as a nutrient and as a hormone, supporting calcium absorption for bone health, immune function, and mood regulation. While the body can synthesize vitamin D from sunlight exposure, many individuals have insufficient levels, particularly in northern latitudes during winter months.

Natural Sources

• Fatty fish (salmon, mackerel, sardines)
• Egg yolks
• Mushrooms exposed to sunlight
• Fortified dairy products and plant-based alternatives
• Sunlight exposure on exposed skin

Zinc

Zinc supports immune function, protein synthesis, wound healing, and sexual health. As a component of over 300 enzymes, zinc is essential for numerous bodily processes. The body does not store zinc, requiring consistent dietary intake.

Natural Sources

• Oysters and other shellfish (highest concentrations)
• Red meat and poultry
• Legumes and nuts
• Seeds (pumpkin seeds particularly rich)
• Whole grains

Magnesium

Magnesium is involved in over 300 enzymatic reactions, supporting muscle function, energy production, nervous system regulation, and bone health. Deficiency is relatively common and can contribute to muscle cramps and fatigue.

Natural Sources

• Leafy green vegetables (spinach, kale)
• Nuts and seeds
• Legumes
• Whole grains
• Cocoa and dark chocolate

Selenium

Selenium functions as an antioxidant and supports thyroid function, immune response, and reduces oxidative stress. As an essential element of selenoproteins, selenium is critical for metabolic processes and disease prevention.

Natural Sources

• Brazil nuts (particularly concentrated)
• Seafood (tuna, halibut)
• Poultry
• Whole grains and legumes
• Eggs

Iron

Iron is essential for oxygen transport through hemoglobin and myoglobin, energy production, and immune function. Two forms exist: heme iron (from animal sources, better absorbed) and non-heme iron (from plant sources, less readily absorbed).

Natural Sources

• Red meat (highest bioavailability)
• Poultry and fish
• Leafy green vegetables
• Legumes and beans
• Fortified cereals

Vitamin B12

B12 is essential for energy metabolism, nervous system function, and DNA synthesis. As it is primarily found in animal products, individuals following plant-based diets require fortified foods or supplementation to maintain adequate levels.

Natural Sources

• Red meat
• Fish and shellfish
• Eggs and dairy products
• Fortified cereals and plant-based products

Calcium

Calcium is critical for bone health, muscle function, and nerve transmission. While bone density peaks in early adulthood, adequate calcium intake remains essential throughout life to slow age-related bone loss.

Natural Sources

• Dairy products (milk, yogurt, cheese)
• Fortified plant-based milk alternatives
• Leafy green vegetables
• Fish with edible bones (sardines, canned salmon)

Vitamin C

Vitamin C functions as an antioxidant, supports collagen synthesis, enhances immune function, and improves iron absorption from plant-based sources. The body cannot store vitamin C, requiring consistent dietary intake.

Natural Sources

• Citrus fruits (oranges, lemons, grapefruit)
• Berries
• Peppers (particularly red peppers)
• Broccoli and leafy greens
• Tomatoes

B-Complex Vitamins

B vitamins (B1, B2, B3, B5, B6, B7, B9, B12) function as coenzymes in energy metabolism, nervous system function, and DNA synthesis. While found in various foods, whole grains, legumes, and animal products are primary sources.

Bioavailability and Absorption

Bioavailability refers to the proportion of consumed nutrients that the body can absorb and utilize. Several factors affect bioavailability:

• Food source: Animal products often provide higher bioavailability than plant sources
• Food combinations: Certain combinations enhance absorption (e.g., vitamin C with iron)
• Cooking methods: Some methods enhance while others reduce micronutrient bioavailability
• Individual factors: Age, digestive health, and genetics affect absorption efficiency

Deficiency Recognition

While severe micronutrient deficiencies are less common in developed countries, marginal deficiencies can still impact health. General signs of potential micronutrient inadequacy include persistent fatigue, muscle weakness, poor immune function, or slow wound healing. These symptoms have multiple possible causes and warrant professional evaluation.