Vitamin D, vitamin C, magnesium and potassium: what are they really for and when to integrate them
Vitamin D regulates the absorption of calcium at the intestinal level and intervenes in the modulation of the immune response, two functions that make it very important. What is often not explained is that it is technically a prohormone, not a vitamin in the classic sense, and that its metabolism involves the liver and kidneys before reaching the active form. For this reason, some conditions – overweight, liver disease, advanced age – compromise its synthesis even in the presence of adequate sun exposure, and make supplementation necessary regardless of the season.
Let’s move on to vitamin C: its most relevant function concerns the synthesis of collagen – therefore the health of the skin, joints, blood vessels – and its ability to regenerate other antioxidants such as vitamin E, creating a multi-level cellular protection system. A little-known fact: chronic stress accelerates its consumption, because the adrenal glands use it to produce cortisol.
A substance that deserves much more attention is magnesium, considering the number of functions in which it is involved. Beyond cramps and sleep, which are the best known aspects, it has a direct role in insulin sensitivity and the regulation of blood pressure. Subclinical deficiencies – those that don’t show up on standard tests because serum magnesium represents only 1% of the body’s total reserves – are probably much more widespread than official statistics report.
Potassium is fundamental in the conduction of nervous impulses and in cardiac contraction, not only in the skeletal muscle contraction with which it is usually associated. Its balance in the body is closely linked to sodium intake, and in contemporary Western diets the ratio between the two is almost always unbalanced in favor of sodium. Sometimes, in fact, it is recommended to reduce the use of salt and increase potassium-rich foods.
How to read the label of a vitamin and mineral supplement
The percentage of nutritional reference value (%NRV) on the label is the first piece of data people look at, but it can sometimes be misunderstood. A product that indicates 100% of the VNR of a nutrient does not mean that it covers the entire daily requirement, because those reference values are calculated on an average adult in standard conditions, without taking into account age, weight, activity level, any clinical conditions or medications taken.
“Another aspect to check is the number of daily dosage units indicated. When purchasing, therefore, it is always a good idea to check what the manufacturer himself suggests: Matt – an Italian brand of the A&D SpA Group, distributed in the best supermarkets, hypermarkets and drugstores – always reports on the label the suggested dosage and the percentage of VNR for each vitamin and mineral supplement in line with the transparency required by an informed consumer. We also remember that the list of substances present should be read from the bottom: the last components are those present in quantity. minor, and often include excipients.
The most frequent errors in the integration of vitamins and minerals
Taking fat-soluble vitamins on an empty stomach is probably the most common mistake. Vitamin D, E, K and A require dietary fat to be absorbed, and taking them in the morning with a glass of water before breakfast drastically reduces their bioavailability.
Another frequent mistake concerns the overdose of fat-soluble vitamins, which, unlike water-soluble ones, accumulate in the body. Vitamin D in particular is subject to this risk when taken in high doses for prolonged periods without blood tests.
Few then consider the interaction between supplements and commonly used drugs. Calcium supplements reduce the absorption of tetracycline and fluoroquinolone family antibiotics. Vitamin K interferes with oral anticoagulants. Magnesium can alter the absorption of some blood pressure medications. These are documented interactions that should be verified before starting any supplementation, especially in people taking chronic therapies.
When integration makes sense and when it is better to review your diet
Those with a documented deficiency need the supplement because the time needed to restore reserves through nutrition alone could be long, and in the meantime the body would continue to function at a deficit.
The diet should be reviewed when the deficiencies are multiple and recurrent, because in that case the signal is clear: it could be the overall approach to the diet that isn’t working. Supplementing three or four nutrients at the same time for months without intervening on what you eat every day is a wasteful and unsustainable approach in the long term.
The starting point always remains the same: knowing where you are before deciding where to go. A complete blood count provides a framework on which to build informed choices.
