The publication of a review of multivitamins by the consumer group Choice sparked quite a bit of media attention in August this year. The sorts of headlines that followed the publication included, “Multivitamins: who needs them?†(Sydney Morning Herald) and “Choice investigation reveals multivitamins are often a waste of money†(News.com.au). These kinds of headlines stay with a reader and create concern even if the report itself is not so extreme in its actual message. Now a new study has come out in support of multivitamins as a way to reduce cancer risk so let’s look at the latest report and also what has been said in recent times.
To begin with the Choice report, what the report did say was that most people can get the nutrition they need from food and that the “worried well†may be spending hundreds of dollars each year on vitamin products that they do not need. The report called for manufacturers to list vitamin and mineral values according to the percentage of an appropriate RDI (recommended daily intake) in each dose to help consumers compare apples with apples.
It is true that food should be your first avenue for gaining nutrition. It is also true that some products include ingredients on their labels at doses that are well below what is required by most people. However, the conclusion that most people will not benefit from a multivitamin supplement is not correct.
RDIs were originally developed to establish how much of the major nutrients people should aim to consume. The US National Academy of Sciences originally developed the RDIs in the 1940s specifically for food production for the military. Since their publication in 1943, the RDIs have been regarded as the authoritative guide on nutrient levels for healthy people. Revisions of the RDIs have taken place over the years. The National Health and Medical Research Council (NHMRC) provided the first RDI tables in Australia in 1954. The most recent revision of the Australian RDIs was completed in 1991. Yet the question is, how does the RDI relate to health? RDIs are calculated as the amount of a nutrient necessary to prevent gross deficiency states such as scurvy from lack of vitamin C or osteoporosis from lack of calcium. They are calculated based on people of average height, weight and nutrient absorption ability, what the NHMRC call the “reference man and womanâ€. Reference woman is 25 years old and 58 kilograms while reference man is the same age and weighs 70kg. They both live in an environment where the average temperature is 18 degrees Celsius. Among other specifics, our reference friends both spend two hours per day slow walking.
Few people in modern Australia fit this “reference†profile.
Higher nutrient levels are necessitated by stress, living in polluted environments, illness, active lifestyles and poor dietary habits. If you drink caffeinated beverages you are flushing some nutrients from your body. If you drink alcohol you are increasing your need for certain nutrients. Being overweight changes your metabolism and your dietary needs and we all know what a problem overweight has become in our society. With climate change ever more evident, it is likely that the average temperature has risen. Then there is the quality of the food we consume to consider. Fruit and vegetables grown in depleted soils and not allowed to ripen on the tree or plant have reduced nutritional value. It all adds up to a difficult scenario in which to gain the nutrition your body needs for optimal health.
Yes, in an ideal world you would get the nutrition you need from your food and not need supplements. In a world where even good food can be low in nutrition, where fast food is far too common, and where lifestyle factors increase your nutritional needs, supplementing your nutritional intake will help many people. It’s true that quality products with adequate dosages are important. To say however, that most people don’t need multivitamins or that multivitamins are not necessary for general health is to miss the bigger societal picture surrounding food production and lifestyle.
In light of all that, let’s look at the new study linking multivitamins to reduced cancer risk.
The study involved 14,641 male doctors and followed them from 1997 to 2011. All participants were aged at least 50 at the beginning of the study. The men were divided into two groups; one was given a daily multivitamin while the other was given a placebo. During the course of the study there were 2,669 cases of cancer and 859 men died from cancer. Those taking the multivitamin had an eight per cent lower chance of developing cancer which is a statistically significant result.
Previous research has shown that people taking multivitamins tend to live healthier lifestyles anyway but in this case the participants were randomly allocated to receive either the genuine multivitamin or a placebo. This design removes the confounding lifestyle factors and predisposition and points to a small but meaningful reduction in risk from multivitamin use.
One swallow does not make a summer and one study does not make a water-tight case but when this study is taken in context of plenty of other research supporting optimum nutrition and wellbeing, then one swallow (if that swallow is of a quality multivitamin) will probably be doing you some good after all.
