As most of us enjoy the unusually hot weather in the UK it is a good time to reflect on how certain vitamin and mineral levels in our body can be adversely affected by heat. A lot of us take the opportunity of such good weather to walk, cycle and play sports. And it’s interesting that studies into the potential loss of certain vitamins and minerals in hot weather are often focused on those undergoing rigorous physical exercise such as sportsman (particularly distance cyclists and runners) and military personnel.
Of course first and foremost we need to try and avoid getting too much sun, protect our skin with a suitable SPF, protect our eyes with sunglasses and keep good hydration with plenty of water and natural juice drinks (and not alcohol nor lots of fizzy or caffeinated drinks).
The heat makes us sweat more and this will affect our levels of water soluble vitamins. The water soluble vitamins are the B-Complex vitamins and vitamin C. Water soluble vitamins are stored in relatively small amounts in our body and cannot be retained for long periods. They are lost through sweat and excretion and hence need regular replacement in the body. Conversely fat-soluble vitamins are stored in our liver and fatty tissues, and are eliminated much more slowly.
A range of diverse studies seem to demonstrate that people suffering from heat exhaustion (or heat stroke) are almost always deficient in vitamin C. So good levels of vitamin C may firstly help reduce the severity of hot weather exposure and robust exercise; secondly poor levels of Vitamin C may exacerbate such episodes of heat and exercise and thirdly a good Vitamin C intake from a suitable source is likely to help speed recovery after heat exposure or exercise.
Indeed Vitamin C has a number of ‘proven’ scientific health claims (from EFSA the European Food Safety Authority) and these include contributing to:
- Protection of DNA, proteins & lipids from oxidative damage
- Normal function of the nervous system
- Nomal energy yielding metabolism
- Maintenance of normal function of the immune system during and after extreme physical activity
Hence Vitamin C rich drinks, supplements or foods (such as fruits) are popular with athletes who need regular intake of vitamins to replace losses after physical exertion.
B-Complex Vitamins are necessary for the normal functioning of the nervous system and may be the single most important factor in the maintenance of the nerves. The water solubility of the B-Complex vitamins means that any excess is excreted and not stored; therefore they must be continually replaced.
Stress and excess alcohol consumption (for example) place a greater burden on our B-Vitamin supply, quite literally ‘burning’ up our reserves. Similarly high B-Vitamin loss due to excess sweating or heat exposure could lead to physical and neurological problems. Pantothenic Acid (Vitamin B5) for example provides a role in contributing to:
- Normal mental performance
- Normal energy yielding metabolism
- Reduction of tiredness and fatigue
Minerals do not have the same ‘classification’ as vitamins in respect of being water or fat soluble. Indeed Mineral absorption and uptake is very different from vitamins and each mineral has its own properties in these respects.
The minerals most commonly identified as suffering significant losses in sweat due to rigorous exercise or overexposure to heat would be: zinc, magnesium, calcium, sodium and potassium. The main source of sodium is of course salt and hopefully we are all aware that excess salt consumption is very bad long-term for us humans. However severe sodium loss due to a prolonged bout of diarhhoea (for example) may mean that a little salt added to water and lemon juice (for vitamin C loss) is recommended.
Zinc is the second most abundant trace mineral in the body, being present in all tissues. Zinc has a wide variety of functions including growth and human development, the healthy functioning of the immune system, and the maintenance of healthy skin, hair, nails and bone. It is related to the normal absorption and action of vitamins, especially the B-Complex.
Zinc is readily absorbed in the upper and small intestine. The body only absorbs as much as it needs at a time; the rest is unabsorbed and about 6mg is lost daily. Too much fibre will not allow zinc to be used because it binds and carries zinc away before it can be accepted by the absorption sites. The largest store of zinc occurs in the liver, pancreas, kidney and bones and voluntary muscles.
Magnesium is an essential mineral that accounts for about 0.05% of the body’s total weight; nearly 70% of the body’s supply is located in the bones. Some 30%-40% of ingested dietary magnesium is absorbed, while the rest is excreted in the faeces.
Magnesium is involved in many essential metabolic processes, including the release of energy from glucose and the synthesis of protein and nucleic acids. Most magnesium is found inside the cell, where it activates enzymes necessary for the metabolism of carbohydrates and amino acids. It also regulates the acid/alkali balance in the body and is necessary for proper functioning of muscles.
Magnesium is absorbed in the small intestine. The rate of absorption is influenced by the parathyroid hormones, the rate of water absorption and the amounts of calcium, phosphorus and lactose in the body. Both magnesium and calcium compete for the same absorption sites. Absorption may be inhibited by other foods and Vitamin D is necessary for the proper utilisation of magnesium.
We can see how important good levels of both the minerals Magnesium and Zinc are to our health. They are two minerals whose levels are influenced by sweat loss and frequently cited in research on athletes who are regularly deficient.
A good multivitamin and mineral will help all family members throughout the year even in the best of weather when optimism and health seem at their highest. A good formula will elevate the nutritional status of people eating average to good diets to optimum levels and it will also elevate the nutritional status of those eating poor diets to an improved level of nourishment and protection.
So in the context of this article we would suggest a formula that has good levels of Vitamin C and B-Complex vitamins, plus other vitamins and a range of minerals – all suited to the individual based on their age, sex and health.
As always when considering taking any supplement the comment above “all suited to the individual based on their age, sex and health” is extremely important. So for example a man is most unlikely to want a multivitamin with Iron, nor a post-menopausal woman; in fact this could be quite harmful to health for such groups. Other common cautions, for example, when looking at multivitamins and minerals are vitamin A levels and women and calcium levels and men.
We would always stress that everybody seeks suitable and qualified advice when looking at purchasing a food supplement – the right advice is very much based on each individual.
If you have any questions regarding this article or any other health matters please do contact me (Amanda) by phone or email at any time. I can also put you in touch with a nutritional practitioner in your area.