Positive Health Online

I am sometimes asked by people if supplements are necessary if eating a balanced diet. In the first place, the concept of a ‘balanced diet’ is vague and a little meaningless for many people, so the initial step is to optimize the diet according to the specific needs of the individual.

However, even then, it may be an uphill struggle, particularly where minerals are concerned, as these vital nutrients have declined in our food over the last 50 years or so, due to modern agricultural methods. The application of fertilisers upsets the balance of minerals resulting in shortage of some; also intensive farming strips the soil of minerals, which are not replaced the following year. Soils are lacking in organic matter which enhance the availability of minerals. In general, modern farming methods increase crop yield considerably, but the quality of the food is poorer.

The most important point about the nature of minerals is that they need to be constantly replaced in the soil; they cannot be made by plants, so once they are taken out of the soil they are gone forever. Commercial fertilisers tend to contain nitrogen, potassium and phosphate, but what about the all-important trace elements such as zinc, manganese, selenium, iron? Organic produce may have a higher nutrient content than non organic food, but again, organic farmers do not replace trace minerals in the soil.

Dr David Thomas studied the nutrient content of various fruit and vegetables and compared them with a nutritional analysis of the same fruit and vegetables of 50 years previously. Even allowing for differences in the analytical chemistry methods between the two periods that measurements were taken, the findings were quite startling.  The foods studied were fruit and vegetables between 1940-1991 and meat and dairy products from 1940-60 and 2002.  Overall there was a 19% loss of magnesium, 29% loss of calcium, 62% loss of copper and 37% loss of iron.

Food aside, there are individual factors relating to genetics, digestion and absorption and an individual’s ability to manage stress, all of which will influence a person’s nutrient status. Add to this ‘anti-nutrients’ such as cigarettes, caffeine, sugar and alcohol, the contraceptive pill and other nutrient robbing pharmaceutical drugs, and demand can often exceed supply where nutrients are concerned.

A review of vitamins for disease prevention by an expert panel published in the highly respected Journal of the American Medical Association concluded that:

“Most people do not consume an optimal amount of all vitamins by diet alone. Pending strong evidence of effectiveness from randomised trials, it appears prudent for all adults to take vitamin supplements”. http://tinyurl.com/c6sdt6g

Next is the subject of a therapeutic intake of a nutrient versus the RDA (recommended daily amount). Many well known over the counter brands of vitamin and minerals boast 100% of the RDA. This sounds impressive in theory. However RDAs are arbitrary figures set by the UK government  to prevent deficiency diseases caused by lack of a particular vitamin, and they are usually very low.

For example, the RDA for vitamin B12 is a miniscule 1mcg but, in studies far more than this has been supplemented to produce a therapeutic benefit. For example 100mcg of B12 was given for 2 years, along with double the RDA of folic acid to older adults. This resulted in improvement on short and long term memory tests for those taking the two B vitamins. http://tinyurl.com/cmguxzk

Similarly, in another study, doses of B vitamins well beyond the RDA (800mcg folic acid, 500mcg vitamin B12 and 20 mg vitamin B6) halved the rate of brain shrinkage in older people with some of the warning signs of Alzheimer’s disease. http://tinyurl.com/329l66v

We’ve always known that women are good at multi-tasking, but it seems that they are even better after taking a multivitamin! This study monitored how the mood and fatigue of a group of 216 women aged 25-50 was affected during and after cognitive tasks. The results were that the women taking a multivitamin and mineral had improved performance (including improved accuracy in multi tasking) compared to the group not taking the supplement.

In another study a B complex supplement improved men’s performance in cognitive tasks.  A group of healthy men were given a daily B complex supplement over a month period. They performed better at cognitive tasks, were less mentally tired and had improved vigour. The supplement was a fairly standard formula which would be found in a good multivitamin & mineral containing  B1 (15 mg), B2 (15 mg), B6 (10 mg), B12 (10 mcg), C (500 mg), biotin (150 mcg), folic acid (400 mcg), nicotinamide (50 mg) and pantothenic acid (23 mg) and minerals: calcium (100 mg), magnesium (100 mg) and zinc (10 mg ).

The concept of a ‘therapeutic’ intake can be applied to many vitamins and minerals and generally such nutrients have an excellent safety record.  Despite the efforts of minority groups to stir up negative press around supplements, there are very few (if any) reports of ill effects from vitamins. Compare this to the thousands of people each year suffering from the side effects of pharmaceutical drugs. In the USA in just one year, there were 100,000 deaths related to drug side effects. That said, it’s always prudent to consult a nutrition practitioner for advice if supplementing long term, other than with a multivitamin.

References

Crystal F Haskell et al. Effects of a multi-vitamin/mineral supplement on cognitive function and fatigue during extended multi-tasking. Human Psychopharmacology  25(6), 448–461. 2010.

Kennedy et al. Effects of high-dose B vitamin complex with vitamin C and minerals on subjective mood and performance in healthy males. Psychopharmacology; 211(1): 55–68. 2010.

Smith AD et al. Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial. Oxford Project to Investigate Memory and Ageing, University of Oxford. 2010.

Walker JG  et al. Oral folic acid and vitamin B-12 supplementation to prevent cognitive decline in community-dwelling older adults with depressive symptoms - the Beyond Ageing Project: a randomized controlled trial. Am J Clin Nutr. 95 (1)194-203. 2012.

Fletcher RH, Fairfield KM. Vitamins for chronic disease prevention in adults: clinical applications. JAMA 19:287(23):3127-9. 2002.

Thomas D. The mineral depletion of foods available to us as a nation (1940-2002) .

Nutrition and Health (19) 21–55. 2007.