There is a common misconception that taking a vitamin pill will improve sports performance. Some are under the false impression that vitamin and mineral supplements can boost the normal metabolic processes when supplied in amounts greater than those provided by diet alone; the rationale being that this might cause an increase in the speed and duration of your metabolism.

While it may appear plausible on paper, there are a number of factors that prove that supplementation will not produce this result.
Vitamins and minerals nutrition | Hillcliff Personal Training North London - Barnet

  Water soluble vitamins will simply be excreted in the urine when optimal levels are achieved, and fat soluble vitamins can be toxic when they exceed requirements
  Over consumption of certain individual minerals and vitamins will have an adverse effect on the absorption of other essential nutrients
  Oral ingestion may not increase supplies at the critical site within the body

Vitamins do not directly provide energy. This comes from macronutrients – carbohydrates, proteins and fats. However, vitamins and minerals play key roles in intermediary exercise metabolism, recovery and adaptation when acting as co-factors in the body’s ability to process and utilise food.

The best way to ensure that the daily requirements for vitamins and minerals are met is through a healthy and varied diet. Because an athlete has to consume more calories in order to fuel the energy expenditure from training, this additional intake should in theory ensure that all micronutrients are provided from food, including any increase in requirements resulting from the demands of increased metabolism. However, certain circumstances dictate that this is not always the case. 

Many of the government and food industry's daily recommendations for vitamins and minerals are estimates of those required for sedentary lifestyles to prevent deficiencies, which may in turn prevent diseases. Not all references are applicable to athletes or those who are very active.

While deficiencies in minerals and vitamins will impair performance, there is no evidence to suggest that supplementing an already sufficient intake will improve performance, either in physical work capacity, endurance, cardiovascular function, muscle strength, oxygen consumption, nor resistance to fatigue. However, there are other clear benefits associated with the consumption of antioxidants.

Nutrients rarely work alone. In order for optimal function and performance to be reached, every nutrient must be available as a resource in sufficient amounts. Any deficit of an individual nutrient will upset the balance. Excessive amounts of any one nutrient may also have a similar effect. This is why it is necessary for an athlete to be aware of the various consequences of taking an individual nutrient supplement. (If iron or calcium deficiency is of concern then an additional supplement may be appropriate. Consult with your GP for bone mass density tests and ferritin level blood samples to be taken to establish whether there is any necessity for an increased dose that could not be met by diet alone.) A multivitamin and mineral approach may be the best option and if taken it's purpose should be as a dietary supplement, rather than an ergogenic aid.

Factors that affect the vitamin content of foods

Much of the food available today is processed and many of the nutrients from the original sources are lost by the time the food reaches the supermarket shelf. We must take this into consideration. With the best will in the world, what would appear to be a healthy diet can be lacking in the necessary nutrients for optimal performance, which is why unprocessed whole foods, along with the freshest produce possible are the best options.

Cooking methods should also be taken into account. Frying and boiling will destroy many of the nutrients. Steaming or stir frying are preferred methods. If choosing juices it is advisable that to consume them as soon as possible after the fruit or vegetable has been juiced. The greater the time left between juicing and consumption, the greater the oxidation and subsequent degradation of nutrient content.


The effects of a nutritional change are dependent on physiological dynamics. Just as with physical training, there is no quick fix. If your nutritional intake is not built on sound principles, no amount of supplementation will result in optimal gains. However, for athletes and those with a highly active lifestyle there is a solid argument that a multivitamin and mineral supplement can provide an insurance policy against possible deficiencies associated with the added requirements of an individual in heavy training.

The most important fact to note is: supplements are not a replacement for a sound diet based on healthy, unprocessed fresh foods.

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