Zinc, Iron, and Vitamin Supplements! Harmful or beneficial and healthy?


The vitamin supplements market is enormous: Americans spend more than 4 billion dollars on food supplements every year – and the trend is rising. In our industry, in particular, the demand for supplements is, of course, huge! 


But are vitamin supplements helpful? 


What about iron and zinc?


The list of supplements that are said to affect your health positively is long, and the recommendations given are often very different! 


As a fitness and personal trainer, you should always have good answers to questions about nutritional supplements and should be able to make appropriate recommendations.



The TOP 4 muscle-building supplements were explained in more detail (click here). 


Zinc, Iron and Vitamin Supplements


Vitamin supplements

No other dietary supplement is sold as often as vitamin supplements. Vitamins are essential because the body cannot produce them entirely. Therefore, they must be ingested through food.



A fundamental distinction is made between water-soluble and fat-soluble vitamins. Unlike the fat-soluble vitamins, the water-soluble vitamins can be excreted with increased intake. Since the fat-soluble vitamins cannot be excreted so easily, one should look carefully here in the case of supplementation to avoid overdosing.



Below are some excerpts from the table mentioned and a rough summary.


Fat-soluble vitamins


Fat-soluble vitamin supplements

These include vitamins A, D, E, and K. In America, the need for fat-soluble vitamins is covered quite well, and deficiencies are relatively rare. 


An exception to this, however, is the well-known vitamin D. More on that in a moment.


Vitamin supplements


Water-soluble vitamin supplements

Here, too, the need for almost all vitamins is covered on average. 


The big exception, in this case, is folic acid (synonymous with vitamin B9) because on average only half of the recommended daily requirement is taken in here. 

Folic acid is essential for the metabolism of genetic material and bone marrow. 


It is mainly found in green leafy vegetables (e.g., spinach). This also explains the frequent lack in the American population: we are not the biggest fans of green leafy vegetables and eat them too little. 


However, if you eat enough of it, you should have no problem with any deficiency symptoms.



Vitamins in their natural form are easier to digest!


Vitamins in their natural form


Vitamin Supplements – Are Our Soils Depleted?

Although vitamin supplements have almost no justification, the marketing is relatively successful. 


For example, it is often claimed that the soil is depleted and that the need for vitamins can therefore no longer be met without food supplements. 


It has not yet been possible to prove that the quality has decreased in the last 50 years!


do vitamin supplements make sense


When do vitamin supplements make sense?


Nevertheless, supplementation can be helpful in various cases.


  1. If there is a proven deficiency: If you have a proven deficiency, it isn’t easy to compensate without dietary supplements. So if you suspect that you have a deficiency (of whatever kind), you should have it checked by a doctor. 


If a deficiency is diagnosed, the individual need should be determined and supplemented in the required amount. 

As soon as the deficiency has been compensated, the requirement should be covered again in the long term through normal nutrition.



  1. With a limited choice of food: Quite a few people are somewhat restricted in their choice of food due to intolerances. For example, if you have fructose intolerance, you should discuss supplementation with your doctor.



Special case vitamin D

As already mentioned, a vitamin D deficiency is not uncommon. There are different types of D vitamins, with D2 and D3 being the best known. Among other things, vitamin D is responsible for:


  • Calcium and phosphate metabolism in skeletal muscle
  • the function of the pancreas
  • skin
  • immune system


In America, depending on the author, only 25-55% of the demand is covered on average. 


The background is that vitamin D is produced almost exclusively by exposure to the sun on the skin. Uptake also decreases with age.


Although one should not necessarily supplement without a proven deficiency, one could make an exception with vitamin D. This is because most of them have a deficiency anyway. Nevertheless, going to the doctor is still the better alternative here. 


vitamin D


Concrete intake recommendations for vitamin D

The following recommendations apply to healthy people. In the case of some diseases (e.g., diabetes), the requirement is different and should be discussed with a doctor as a matter of urgency.


The DACH reference values ​​of 800 IU (International Units) are now considered too low. Some people even need more than 4000 IU. To calculate the need a little more precisely, use the following formula:


Vitamin D requirement in IU = weight in kg x 40-60 IU 


A person with a bodyweight of 70 kg would require 2800 to 4200 IU. These amounts are harmless to health from supplementing – even without regular laboratory tests


In the best case, vitamin D is taken with a high-fat meal, as it is better absorbed. 


If a deficiency has already been proven, the “starting dose” may also be higher than the formula would produce. 


However, the exact calculation of a proven deficiency would go beyond the scope and should be left to the doctor. 


Read also:


Vitamin D2 or D3?

Whether supplementing D2 or D3 makes more sense has not yet been finally clarified because the study situation is not entirely clear


However, vitamin D is probably a better choice for supplementation. It would help if you also took vitamin D3 with vitamin K2.



Do athletes have an increased need for vitamins?

Yes! However, athletes also have a generally increased energy requirement. The increased food intake usually covers the increased need for vitamins.



Interim conclusion

Anyone who eats a balanced and wholesome diet will not experience any benefit from supplementation. If you suspect a deficiency (e.g., folic acid), you should consult a doctor before taking action yourself. If you suspect a vitamin D deficiency, it makes sense to consult a doctor. 


However, vitamin D could also be supplemented without regular laboratory tests if one follows the formula mentioned.



Overdose Supplements

Overdosing when supplementing with vitamins is possible. The fat-soluble vitamins (A, D, E, K) are of particular concern. These can accumulate in the body and damage organs. 


Below are some ex566amples of overdoses and their consequences.


Vitamin A or beta-carotene (a provitamin – must first be converted to vitamin A): 


Overdose can increase the likelihood of lung cancer or jaundice in smokers.


Vitamin C: Taking too much vitamin C can promote kidney stones and diarrhea.


Vitamin E: Vitamin E in increased amounts can inhibit blood clotting.


Multivitamin supplements


Multivitamin supplements

For the reasons already mentioned, multivitamin supplements are not recommended for the general public. 


Usually, you only have a specific deficiency. The other vitamins could then have overdosed. 


All in all, it can be said: that the natural intake of vitamins is ahead! 


It is not difficult to cover the vitamin requirement, and an overdose is not possible with natural foods. 



Remember: Vitamins in their natural form are easier to digest!



Iron Supplements


Iron Supplements

Iron is an essential nutrient. Among other things, it is responsible for transporting oxygen and immune and brain function. 


Symptoms of a deficiency:


  • less power
  • fatigue
  • immune system weak


In general, iron deficiency is not very common in western countries. Affected somewhat more frequently are small children, pregnant women, and women before menopause. 


Even if it does happen, a deficiency should be identified before supplementing.



Iron requirement

The need for iron fluctuates. While adult men should consume about 10mg per day, it is 15mg for premenopausal women. 


The background is that women have an increased iron requirement due to menstruation. 


Pregnant women should even take 30mg a day. 


On average, 13.5 mg are taken in America – a good value.



Iron supplementation

If there is a proven deficiency, you should supplement iron – otherwise, not. Too much iron can also have negative effects. Iron intake is not necessarily a problem for vegans either.


Although omnivores mainly get it from the meat, there are also numerous vegan suppliers:


  • Pumpkin seeds (11/100g)
  • Sesame + hemp seeds (10mg/100g)
  • Linseed (8mg/100g)
  • Oatmeal (5.8mg/100g)
  • and much more



Zinc Supplements  

Zinc Supplements

Zinc is involved in almost all vital processes in the body. Accordingly, a zinc deficiency would be quite unfavorable. 


Unfortunately, zinc is stored relatively poorly, which means that continuous intake is essential.


Zinc deficiency symptoms


  • growth disorders in childhood
  • disorders of the immune system
  • deterioration of wound healing
  • Disturbance of protein, carbohydrate, fat, and insulin metabolism
  • worsening of taste perception 
  • Decrease in semen quality in men 


Vegan zinc suppliers


Vitamin supplements for Vegans and special phases of life

Vegans and vegetarians can also meet their needs. However, since absorption is somewhat poorer here, vegans should consume slightly more zinc than omnivores. 

Check our best vegan recipes here! It brings fantasy and joy into your kitchen…


Vegan zinc suppliers are:


  • legumes
  • Grain
  • full grain
  • nuts
  • seed


You should pay more attention to your zinc requirements in some phases of life. Pregnancy, lactation, and childhood should be mentioned above all.



Zinc requirement

The DGE recommends a daily intake of 10 to 15 mg for adults. In America, an average of over 10 mg is taken in. 


A daily intake of 25 mg per day is specified as the maximum amount in Europe – side effects are to be expected above this. 


Since the 25mg is relatively close to the 15mg, you should – if at all – supplement carefully. 


The same applies here: first, have a deficiency determined and then supplement.



vitamin supplements conclusion


Zinc, Iron, and Vitamin Supplements – Conclusion

All of the supplements mentioned should not be taken over a long period of time, even if there is a proven deficiency (except for vitamin D). 


After a balanced deficiency, it would be desirable to be able to cover the requirement again in the long term through normal nutrition.

If you need help with healthy recipes, I highly recommend this special custom diet program.

In principle, you should not supplement any of the food supplements presented without the individual advice of a specialist, as some of them can lead to an overdose. 


Vitamin D could also be supplemented without regular laboratory tests – nevertheless, going to the doctor is the better option.