Micronutrients Guide

Micronutrients are nutritional substances the body needs in small amounts, but don't let that fool you. Their importance is enormous. Unlike macronutrients (proteins, carbohydrates, fats), they don't provide energy per se, but they're involved in hundreds of biochemical reactions that keep everything running: immunity, energy production, mood, bone health... none of it works without them.

They fall into two main families. Vitamins are organic molecules, there are 13 essential ones, that the body can't produce in sufficient quantities on its own. Minerals and trace elements are inorganic substances like calcium, iron, zinc, and iodine, equally indispensable for proper function.

A varied, colorful diet generally covers all these needs. But certain groups, vegans, pregnant women, older adults, may have specific requirements that justify targeted supplementation.

Vitamins A, D, E, and K share one defining characteristic: they dissolve in fat, not water. This means they're stored in the liver and fatty tissues, and they require dietary fat to be properly absorbed. Eating a carrot salad without a drizzle of olive oil? A significant portion of the vitamin A simply passes through.

Vitamin A (retinol) is well known for its role in vision, especially night vision, but it also supports immunity and skin health. Liver, carrots, sweet potatoes, and spinach are top sources. Vitamin D (cholecalciferol), often called the "sunshine vitamin," is synthesized by the skin during UV exposure. It's essential for bone health, immune function, and even mood regulation. Deficiency is especially common in winter in temperate climates, which is why seasonal supplementation is often recommended.

Vitamin E (tocopherol) acts as a powerful antioxidant, shielding cells from oxidative damage and supporting cardiovascular health. Vegetable oils, nuts, seeds, and avocados are rich sources. Finally, Vitamin K (phylloquinone) plays a central role in blood clotting and bone mineralization. Leafy green vegetables, broccoli, and cabbage are your best dietary allies.

Unlike fat-soluble vitamins, vitamin C and the B vitamins dissolve in water and aren't stored in significant quantities by the body. Excess amounts are excreted in urine, which limits toxicity risk, but also means a regular, varied intake is essential.

Vitamin C (ascorbic acid) is probably the most well-known. It acts as an antioxidant, supports the immune system, and is essential for collagen synthesis, which means it's critical for skin, tendons, and bones. Citrus fruits, kiwi, bell pepper, and broccoli are among the richest sources.

The B vitamin group includes eight distinct vitamins, each with its own role. B1 (thiamine) supports energy metabolism and the nervous system. B2 (riboflavin) and B3 (niacin) are involved in energy production and skin health. B6 (pyridoxine) is key for protein synthesis and immune function. B9 (folate) is critical for cell division, particularly important during pregnancy to prevent certain birth defects. B12 (cobalamin), finally, is essential for the nervous system and red blood cell formation.

Important note: Vitamin B12 is absent from plant foods. Anyone following a vegan diet must supplement without exception, this is one of the few truly non-negotiable supplementation needs.

Minerals are inorganic elements the body needs in relatively large quantities, over 100 mg per day, to maintain its essential functions.

Calcium is the most abundant mineral in the human body. Most people think of bones and teeth, but it also plays a fundamental role in muscle contraction and nerve signaling. Daily needs for adults range from 900 to 1,200 mg, met primarily through dairy products, canned sardines with bones, tofu, and some leafy greens.

Magnesium is often overlooked, yet it participates in over 300 enzymatic reactions. Energy production, stress management, sleep quality, blood sugar regulation, its reach is remarkable. Daily needs are around 300 to 400 mg, and deficiency is common in modern societies, largely due to chronic stress and overly refined diets. Nuts, whole grains, legumes, and dark chocolate are your best sources.

Potassium plays a key role in the body's fluid balance, heart function, and blood pressure regulation. With daily needs around 3,500 mg, a diet rich in bananas, potatoes, avocados, and legumes generally covers them without effort. On the flip side, sodium is a mineral most of us consume far too much of: recommendations suggest staying under 2,000 mg per day (roughly 5 g of salt), while processed foods routinely contain far more.

Trace elements are minerals the body needs in tiny amounts, less than 100 mg per day, but their absence is felt quickly.

Iron is perhaps the most widely known, largely because iron-deficiency anemia is the most common nutritional deficiency worldwide. Its main role is transporting oxygen in the blood via hemoglobin. Needs vary by profile: around 8 mg/day for men, up to 18 mg/day for women of childbearing age. Red meat and liver are the richest sources, but legumes and spinach also contribute, as long as they're paired with a source of vitamin C, which dramatically improves the absorption of plant-based iron.

Zinc is a quiet but essential mineral for immunity, wound healing, and even the perception of taste and smell. Oysters are the most concentrated source, followed by meats, pumpkin seeds, and legumes. Selenium, found in Brazil nuts (just 1–2 per day cover your daily needs), fish, and meats, acts as an antioxidant and supports thyroid function.

Iodine is essential for producing thyroid hormones, which regulate metabolism. Prolonged deficiency can lead to hypothyroidism and a chronic fatigue that's difficult to identify. Fish, seaweed, iodized salt, and dairy products are the main sources. Copper, finally, contributes to collagen formation, iron metabolism, and antioxidant defense, found primarily in organ meats, nuts, legumes, and shellfish.

Our bodies constantly produce free radicals, unstable molecules generated by normal metabolism, but also by stress, pollution, tobacco, and poor diet. In excess, these free radicals damage our cells and accelerate aging: this is oxidative stress. Antioxidants are the guardians that neutralize them.

Vitamins C and E are the best-known antioxidants. They protect cells from oxidative damage and work synergistically, vitamin C actually "recharges" vitamin E after it acts, making them a particularly effective duo.

Carotenoids are a large family of plant pigments with remarkable antioxidant properties. Beta-carotene (a precursor to vitamin A) gives carrots and sweet potatoes their orange color. Lycopene, responsible for the red color of tomatoes and watermelon, is associated with a reduced risk of certain cancers. Lutein and zeaxanthin, found in spinach and corn, specifically protect eye health.

Polyphenols are the most diverse family: flavonoids from berries, apples, green tea, and cocoa; resveratrol from red grapes and wine (in moderation); curcumin from turmeric, recognized for its anti-inflammatory properties. To maximize your intake, focus on diversity: a colorful plate, generous use of spices, unsweetened green tea, and a variety of nuts are the simplest and most effective strategy.

Intermittent fasting and micronutrients have a relationship that doesn't get talked about enough. Narrowing your eating window has real implications for how the body absorbs, uses, and manages these essential nutrients.

During the fasting period, an interesting mechanism kicks in: cellular autophagy, the process by which cells recycle their damaged components, becomes more active. With no incoming nutrients, the body optimizes how it uses its existing resources. Electrolytes (sodium, potassium, magnesium) deserve particular attention: urinary excretion increases during fasting, which can lead to noticeable drops, especially in the first few weeks of adaptation.

During the eating window, the challenge shifts: concentrating all your nutritional intake into one or two meals demands particularly nutrient-dense food choices. Colorful vegetables, quality proteins, healthy fats, and whole grains stop being options and become priorities. B vitamins (especially B12 for vegetarians), iron, and calcium warrant extra attention, as they're the nutrients most likely to fall short when meal volume is reduced.

The real trap to avoid: shrinking your eating hours without changing the quality of what you eat. Fasting doesn't fix a micronutrient-poor diet, it can actually make deficiencies worse if you're not paying close attention to the nutritional density of every meal.

To explore overall nutrition further, also check out our guide on macronutrients.

The information presented in this guide is provided for educational and informational purposes only. It does not constitute personalized medical or nutritional advice, and should not replace a consultation with a qualified healthcare professional.

Micronutrient needs vary significantly by age, sex, health status, activity level, and any existing medical conditions. Certain groups, pregnant women, vegans, older adults, competitive athletes, have specific needs that require tailored guidance.

Consult a healthcare professional (doctor or registered dietitian) before starting any supplementation, especially if you have a chronic illness or suspect a deficiency.