Which Dietary Supplements Are Useful? A Supplement Guide

A vitamin D deficiency can occur when you get little sunlight exposure, which is often the case in winter. Elderly individuals and infants are also at higher risk. Typical symptoms include fatigue, a weakened immune system, muscle and bone weakness, and pain.

Supplementing with vitamin D can be especially beneficial during winter months, as it also enhances calcium and phosphorus absorption in the body. This helps maintain strong bones and teeth, which is why it is sometimes prescribed for osteoporosis prevention.

Calcium is found in many foods, especially dairy products. Deficiency is common in people with lactose intolerance or those following a vegan diet. Other risk factors include menopause and certain conditions like Cushing’s syndrome. Symptoms may include brittle nails, muscle cramps, and an increased risk of osteoporosis.

Calcium supplements, often combined with vitamin D, can promote bone health. A diet rich in dairy products can also help prevent calcium deficiency.

People who consume little fatty fish or healthy fats (see our article) often lack omega-3 fatty acids. Pregnant and breastfeeding women also have an increased need. Scientific studies confirm that adequate intake supports healthy blood pressure, heart function, vision, and brain function. Additionally, omega-3s play a crucial role in fetal development.

Omega-3 supplements, such as fish oil or algae oil (for vegans), can help improve intake. However, small dietary adjustments can also be effective: eating more seafood, adding a few teaspoons of chia seeds to breakfast, or incorporating coconut oil, hemp oil, olive oil, or flaxseed oil can work wonders.

Magnesium deficiency typically occurs when the body loses a lot of fluids, such as in elderly individuals taking diuretics or laxatives. Intense physical activity or gastrointestinal disorders can also lead to fluid and magnesium loss. Common symptoms include fatigue, muscle twitches, and cramps.

Magnesium supplements can help meet this need. Magnesium-rich mineral water (at least 50 mg per liter) is also beneficial and often sufficient during physical exertion.

Zinc is primarily found in animal products such as meat, fish, cheese, and eggs, in smaller quantities also in legumes and nuts. A deficiency is more common in individuals with restricted diets, such as vegans. Additionally, athletes may experience zinc loss through sweating. Symptoms include a weakened immune system and poor wound healing.

Zinc supplements can help, but they should not be taken in excessive amounts, as zinc is a heavy metal and overdosing can lead to toxicity.

Iron deficiency is particularly common in women of childbearing age due to menstrual blood loss. Pregnant women, vegetarians, and vegans may also experience deficiencies. Iron is essential for oxygen transport in the body, and a deficiency can lead to fatigue, lack of motivation, paleness, shortness of breath, and concentration problems.

Iron supplements, such as iron(II) gluconate, can help, and they are often taken with vitamin C to enhance absorption. The belief that spinach is high in iron is somewhat misleading—while spinach contains about 3.4 mg of iron per 100 grams, it also contains vitamin C, which aids absorption. However, our bodies absorb iron from animal sources more efficiently than from plant sources, which is one reason plant-based diets may lead to deficiencies.

The highest iron content is found in animal liver, ranging from 7 to 20 mg per 100 grams, depending on the source and preparation. Plant-based alternatives include sesame seeds (approx. 10 mg per 100 grams), pistachios (approx. 7.3 mg), cashews (approx. 6.3 mg), and chanterelle mushrooms (approx. 5.8 mg).

Probiotics are beneficial bacteria that naturally inhabit our intestines and contribute to a healthy gut microbiome. A diet low in fiber and high in processed foods, alcohol, coffee, or soft drinks can disrupt gut flora. Antibiotic use also kills off good bacteria, further affecting gut health. An imbalanced gut can lead to allergies, food intolerances, skin problems, bloating, or frequent infections.

For this reason, probiotics are often prescribed alongside antibiotics. Those looking to support gut health can take over-the-counter probiotics from the pharmacy or focus on a plant-based, fiber-rich diet.