Are you concerned you may have a vitamin or mineral deficiency? Or do you currently take a multivitamin supplementation currently because you think you should? We talk to nutritional therapist Tracy Tredoux for some expert advice on symptoms, the fine balance of vitamins and minerals required for the body and how it is best to supplement your diet, if you need to.

These days nutritional deficiencies are becoming widespread. In the past 60 years, there have been fundamental changes in the quality of our food and, as a result, our food sources are not providing us with the same nutritional benefits they did generations ago. Growing methods, source, preparation and ultimate presentation of basic staples have changed to such an extent that nutritional contents have been severely depleted. These changes are significant contributors to rising levels of diet-induced ill-health. But does the answer to this modern-day malady lie in nutritional supplements?

The function of vitamins and minerals

Vitamins are essential for our bodies to function properly. Our bodies make some vitamins but often not in sufficient enough quantities to meet our daily demands. Other vitamins, such as vitamin C, are not made by the body and therefore have to be obtained through the food we eat. Minerals are elements that originate in the Earth and always retain their chemical identities. Our bodies processes depend upon the action of minerals to support numerous bodily functions we often take for granted. Minerals are divided into two categories: macrominerals and trace minerals/trace elements. Macrominerals (calcium, magnesium, phosphorus, potassium) are required by the body in larger quantities (more than 100mg daily) than trace elements (chromium, copper, fluoride, iodine, iron, selenium, zinc). Even though our bodies require very small amounts of trace elements, they are no less important than macrominerals or any other nutrients and a deficiency can result in chronic and debilitating symptoms and health consequences.

How to identify vitamin or mineral deficiencies

Vitamin and mineral deficiencies often present with physical symptoms. Some deficiencies may lead to only minor symptoms, while others can result in quite severe, ongoing, chronic health problems.

Iodine, for example is a trace element that, although only required in small amounts, can lead to hypothyroidism symptoms when deficient. Symptoms of iodine deficiency include depression, lethargy, difficulty losing weight, memory problems, dry skin, constipation, brain fog, cold hands and feet, recurrent infections, thinning hair. These symptoms should prompt you to a visit to the doctor, who will perform a blood test to ascertain your thyroid hormone levels. Iodine is the building block of both T3 and T4. If deficient in iodine this can result in low levels of these hormones. Deficiencies can be remedied by eating iodine rich foods, such as seaweed, cod, cranberries, plain yoghurt, baked potato, raw milk, shrimp, eggs, dried prunes or by supplementing.

Selenium is another example of a trace element which plays an important role in the body. The amount of selenium in food sources is largely determined by the quality of the soil used to grow them. Selenium is an important mineral which supports the function of the endocrine, immune and cardiovascular systems. Symptoms of selenium deficiency include infertility, muscle weakness, mental fog, fatigue and a weakened immune system. A selenium deficiency, as with an iodine deficiency, can result in the symptoms of hypothyroidism. 2 Brazil nuts a day ensures that we are getting our recommended daily amount. As with all minerals, high levels of selenium can be toxic so one must be careful not to eat handfuls of Brazil nuts daily.

There is no set of symptoms that will cover all deficiencies. Each nutrient has its own unique role and therefore each deficiency will come with its own unique set of symptoms, which will often overlap with those of other deficiencies. Because of this ambiguity, whenever your symptoms indicate a possible vitamin or mineral deficiency, it is important to test, rather than guess. Today, most GPs test serum vitamin D levels, calcium, potassium, iron levels, certain of the B vitamins, magnesium and zinc by taking a blood draw. There are other nutritional tests available for targeted nutritional supplementation such as The ONE (Optimal Nutritional Evaluation) FMVTM from Genova Diagnostics, which provides an analysis of key nutritional biomarkers in one convenient urine collection.

How to supplement


The purpose of identifying and rectifying nutrient deficiencies is to equip and support the body to do what it is designed to do. However, it is important to understand the intricate balance that can very easily be upset by taking too much of one vitamin or mineral at the expense of another. Every single vitamin and mineral has an effect on other vitamins and minerals in the body. For example:

  • Today, vitamin D supplementation is the new ‘best thing since sliced bread’ and people are being advised to take levels as high as 5-10,000 IU daily. However, high levels of vitamin D drives down potassium and can result in excess calcium in the blood. This slows down metabolism and increases the potential for calcification and arterial cirrhosis, especially in a magnesium deficient body.[1]
  • Too much iron in the body is toxic. Humans survive by constantly recycling iron, a metal which is an essential component of red blood cells, but which is toxic outside those cells. In contrast to iron uptake and recycling, there is no bodily mechanism for excreting iron. Those with dangerously high levels of iron can donate blood to bring down these levels. Too much iron can lead to life-threatening conditions, such as liver disease, heart disease, viral and bacterial infections (iron feeds pathogens in the body) and cancer. It is important to remember that numerous foods are fortified with iron and most multivitamin supplements contain iron. Excess iron depletes vitamin C and zinc levels. More importantly, there is a poorly understood relationship between iron and copper metabolism in our bodies. Some cases of iron deficiency anaemia cannot be relieved by taking iron but can be successfully treated by the consumption of copper.
  • Excess zinc depletes copper. It is well known that a zinc deficiency affects the skin, the brain, the central nervous system, the immune and reproductive systems. Many people know to take zinc when they are feeling under the weather but do not realise that this can lead to a copper deficiency.

The above examples illustrate the importance of understanding the fine balance between all these vitamins and minerals. In an ideal world, the best source of vitamins and minerals is the food that we eat. The nutrients found in food have a complex and synergistic relationship with each other and with other nutrients, such as phytonutrients or antioxidants, and thus a more powerful effect on the body than simply isolating one nutrient. Eating a diverse and wide variety of organic, chemical free foods is the best way of giving our body the daily micronutrients it requires. However, this is often not realistically achievable and the reason taking supplements becomes necessary for optimal health.

Most supplements do exist in a wholefood form and, as a nutritional therapist, I prefer to keep supplementing as close as possible to what nature intended. Many people may be unaware that some of the synthetic forms of certain vitamin Bs are derived from coal tar and processed with several harsh chemicals, including ammonia and formaldehyde. On the other hand, bee pollen is a wonderful, natural source of many of the B vitamins. Likewise, cod-liver oil (as take by our grandparents) is a good natural source of vitamins D and A (retinol).

No article on vitamins and minerals would be complete without mentioning the critical role that magnesium plays in our bodies. It is our number one mineral, involved in about 300 chemical reactions taking place daily and crucial for the proper functioning of around 3700 enzymes. In fact, many known illnesses are associated with a magnesium deficiency and it is often the missing cure. Symptoms of magnesium deficiency include restless legs, insomnia, muscle pain, fibromyalgia, anxiety, high blood pressure, type 2 diabetes, fatigue, headaches and Osteoporosis. Dark chocolate, avocado, nuts and seeds, legumes, wholegrains, bananas and leafy greens are good food sources of magnesium. L Threonate is a form of magnesium that has a superior ability to penetrate the mitochondrial membrane and is considered to be the best magnesium supplement on the market. Magnesium Citrate has a laxative effect and helps with constipation. Magnesium and Epsom salt baths in the evening are a great way to relax, destress and to detoxify. Most calcium-magnesium supplements come in a 2:1 ratio. However, there is growing evidence pointing to high calcium, low magnesium intake as leading to calcification, or hardening of the arteries (atherosclerosis being no.1 cause of death in the U.S), osteoporosis and bone fractures. Many people find taking 350-400mgs of magnesium at night helpful for the relief of a myriad of symptoms.


Vitamins and minerals are vital in supporting a healthy diet and lifestyle. A healthy balanced diet should provide the body with all the micronutrients it needs. However, with the increase in processed, chemical sprayed foods and depleted soils, supplementing our diet is becoming more and more necessary. Taking a daily multi vitamin and mineral supplement in the hope of covering all requirements can often throw your body out of balance. We are all different and have different vitamin and mineral requirements and balances. Test, don’t guess and beware the trap of the ‘one size fits all’ approach resulting in supplementing without understanding your own body’s unique micronutrient levels and requirements. Good quality food and food sourced nutrients are always best where possible.

[1] Ito M, Cho BH, Kummerow FA (1990) Effects of a dietary Magnesium deficiency and excess Vitamin D3 on swine coronary arteries. Journal of American College of Nutrition 9(2): 155-163.

Tracy Tredoux is a fully qualified Nutritional Therapist, living and working in London. When not giving talks or consulting with clients, she writes health and nutrition articles, tips and recipes which you can find on her website. Follow Tracy on Twitter (@TracyTredoux) for further updates and tips.

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