This subject can be a real minefield. Many professionals argue that if you consume “a healthy balanced diet” there will be no need for any supplementation. On the other hand supplements are big business and many consumers have been persuaded that it is advisable to take various supplements or even a mixture of vitamins and minerals just to be on the safe side.
Unfortunately there are no easy answers. However anyone who takes a supplement needs to be aware that some of them may do more harm than good. In this blog I will highlight some of the issues which ought to be taken into consideration when deciding on which supplements to use.
Calcium and related minerals and vitamins
Based on an analysis of data from about 12,000 participants from 11 different trials it was found that those taking calcium supplements were associated with about a 30% increase in the incidence of myocardial infarction and smaller, non-significant, increases in the risk of stroke and mortality (1).
Although it is generally believed that calcium deficiency increases fracture risk and that it can be reduced by calcium supplementation there is no credible scientific evidence to justify this approach (2). Those investigations which have been done are open to serious criticisms. For example in some studies dropout rates were high and adherence to treatments was poor. By contrast there is some evidence which suggests that calcium supplementation of patients with osteoporosis may be associated with an increase in the incidence of bone fractures of up to 50% (3).
It has been known for many years that an adequate supply of Vitamin D is required for the effective utilisation of calcium. However it clear from research conducted over the past 30 years that Vitamin D has many different functions in the body (4). Although it can be produced in the body, this is critically dependent on exposure to sunshine. In countries such as the UK and Ireland there is simply not enough sunshine during the period from late autumn to early spring to enable an adequate supplied to be produced. This means that the vast majority of the population suffer from an insufficiency of vitamin D. There is very convincing evidence that those with high body levels of Vitamin D have lower rates of heart disease and various cancers which results in increased life expectancy when compared with those who have low levels.
While it is possible to boost the intake by diet, the requirements are unlikely to be achieved by this means. If it is accepted that the requirements are determined by the levels reached when exposed to sunshine then about 5000 International Units (IU) would have to be consumed every day. Regrettably the official Recommended Daily Allowances are of the order of 400 IU which is far too low. Hence many people are lured into a false sense of security because they quite naturally assume that if they comply with the official advice all will be in order. Ideally one should know the level of Vitamin D in the blood but this is rarely measured. From a public health perspective there is an overwhelming case for a national programme to determine the blood levels of Vitamin D so that steps could be taken to overcome any deficiencies that are uncovered. On the basis of our current knowledge this probably applies to most people, especially during the January-March period when any reserves built up the previous summer will have been used up.
It is also absolutely crucial to ensure that there is an adequate supply of Vitamin K2 which is essential for the calcium and Vitamin D to be utilised effectively (5,6). It is only in the last 12 years or so that the importance of Vitamin K2, which must not be confused with Vitamin K1, has been appreciated. In a study conducted in Rotterdam, it was found that those in the highest tertile (third) of vitamin K2 intake had a reduction of over 50% in the death rate due to heart disease when compared with those in the lowest tertile. This study also found that the degree of calcification in the aorta inversely related to the amount of Vitamin K2 consumed. This is consistent with the view that the Vitamin K2 is essential for the utilization of the calcium. Furthermore in the absence of Vitamin K2 the calcium is free to play a role in calcification and may even be the primary cause of the process. The main dietary sources of vitamin K2 were eggs, meat and cheese. Hence those who limit their consumption of these foods may unwittingly be restricting their intakes of Vitamin K2.
Finally, I should point out that there is frequently a deficiency of the mineral magnesium. Research in Finland, where there was one of the highest incidences of heart disease in the world. In the period 1973-1999, revealed that the ratio of calcium to magnesium was 4. In the USA which also has a very high death rate due to heart disease the ratio is 3.5. Official recommendations are that the ratio should not be higher than 2 and ideally should be close to unity(7). The main sources of magnesium in the diet are green leafy vegetables, nuts and seeds. Organic sources are probably to be preferred because it is less likely that the soil will have been depleted of magnesium. Better still, grow your own!
Here is another instance where consideration of a single nutrient, namely calcium can result in more harm than good. It is crucial to recognize that increasing calcium may also have an effect on the requirements for other nutrients as this example demonstrates. So if you decide you are going to take a supplement make sure you fully appreciate any impacts on the requirements for other nutrients.
- M J Bolland et (2010) British Medical Journal 341, c3691
- E Seeman (2010) Clinical Journal of the American Society of Nephrology 5, S3-11
- E Cumming et al (1997) American Journal of Epidemiology 145 pp 926-934