While I am an ardent advocate of nutritional medicine, my career in it was almost snuffed out before it began. Just as my interest in the subject was burgeoning, I found myself aghast at what seemed to be the excessive quantities of nutrients punted by many natural-health experts. Often, I found recommendations for the unsuspecting public to take several times the recommended daily allowances (RDAs) I had learnt at medical school. I questioned whether taking what seemed to be super-stratospheric levels of vitamins and minerals was safe. I also wondered what purpose this megadosing might serve (other than making very expensive urine, that is).
For the past half-century, the RDAs for vitamins and minerals have formed the basis for conventional nutritional wisdom. The commonly held belief is that as long as the RDAs are met via our diet and/or supplements, our nutritional needs will be amply covered. However, as I delved deeper into the subject of nutrition, it occurred to me that despite their hallowed place in nutritional dogma, the evidence suggests that the RDAs are set too low, and are well overdue for review. There is a wealth of research that shows benefits from taking nutrients in doses higher than the RDA. Despite this, it turns out that European legislation has been drafted which, if passed, will make the sale and purchase of useful quantities of nutrients simply illegal.
The RDAs actually represent the level of vitamins and mineral nutrients needed to prevent nutrient deficiency. One common misconception about the RDAs, however, is that they represent what are deemed to be the 'safe' levels of nutrient intake. Many individuals fear that taking much more than the RDA of a nutrient puts them at risk of toxicity and overdose. However, the fact is the RDAs are not designed to reflect the safe levels of nutrients at all. The amount of a nutrient that can be safely taken is often many times the RDA. For instance, while the RDA for vitamin B6 is just 2mg, its upper safe limit is at least 200mg. Another example is vitamin B12, which has an RDA of 1mcg and a safe daily limit of at least 500 times this amount.
For me, a major deficiency of the RDAs is that while they represent the minimum levels of nutrients needed to prevent an obvious deficiency, they in no way reflect the optimum levels of nutrients required for optimum health. For example, while 60mg of vitamin C each day is deemed to be enough to stop our teeth falling out due to scurvy, this dose is very unlikely to keep our body in tip-top shape. Vitamin C intake has been correlated with a reduced risk of heart disease and cancer, and there is good evidence that supplementing with vitamin C can increase longevity, too. More and more evidence suggests that each of us should be consuming at least 200mg of vitamin C each day, and it may well be that much higher levels (perhaps several grams per day) are required for peak health and during illness.
Another example of the yawning abyss that often exists between the RDA and more optimal levels of a nutrient concerns vitamin E. Two large studies published in the New England Journal of Medicine in 1993 demonstrated that supplementing with 100IU of vitamin E for at least two years reduced risk of heart disease in both men and women by about 40 per cent. Despite this, the RDA for vitamin E remains at a measly 10IU.
A critical shortcoming of the RDA system is that it simply fails to cover some of the nutrients known to be critical to health. Currently, RDAs exist for only 18 vitamins and minerals. Yet it is well established that we require 50 or 60 nutrients to sustain life. It is clear that several key nutrients are omitted from the RDA system. A good example is the trace mineral selenium. This antioxidant nutrient has been linked with a reduced risk of chronic illnesses, such as cancer. One study found that supplementing with selenium at a dose of 200mcg per day significantly reduced the risk of dying from cancer. To this day, no RDA for selenium exists. Other key nutritional players for which no RDA exists include betacarotene, chromium, copper and manganese.
Currently, UK law permits that supplements containing decent levels of nutrients (often many times the RDA) can be freely sold. This is in stark contrast to most EU members, including France and Germany, which have set upper limits of nutrients based broadly on their RDAs. Currently, the EU is seeking to harmonise food-supplement law. In all likelihood, it looks as if the UK's desire for supplement dosages based on true safety and freedom of choice will be thwarted by the collective might of the other EU member states. Not only do these proposed measures fly in the face of good scientific evidence, but it seems likely that they will only add to the burden of chronic disease and ill health in this country.
Dear John
I have a question for you on the subject of juicers. Are the nutritional benefits of drinking juiced fruit and vegetables comparable to eating the food raw? If not, what is lost in the juicing process?
Gavin Smith, Ilkley, West Yorkshire
The health benefits of juicing are often extolled by nutritionists and health experts. Juicing is believed to make the nutrients in fruits and vegetables more readily available to the body. In this way, some individuals believe that juicing actually improves the nutritional value of fruit or veg. However, as you suggest, something can be lost in the juicing process, too. The majority of the fibre, for instance, is discarded during juicing. And that's not all: within that fibre there are quite likely to be nutritional elements that may have health-giving properties. For instance, citrus-fruit pith contains substances called bioflavonoids that are known to have beneficial actions in the body.
Clearly, juicing has its pros and cons. Overall, I'm a fan. However, because of the issues surrounding lost fibre and nutrients, I recommend blending, too. Blending (liquidising) food generally makes it more digestible, but retains elements that juicing may sacrifice. Vegetables don't tend to blend well and are therefore probably better juiced. However, fruits (especially bananas, mango and berries) are generally good for blending, and make fabulous smoothies with a little water, ice and maybe some yogurt.
Nutrition news: Roll with the oats
Coeliac disease is a condition caused by sensitivity to a protein called gluten. When coeliac sufferers eat gluten, changes in the intestinal wall can interfere with the absorption of nutrients from food. The traditional coeliac diet is one that eschews the gluten-containing foods wheat, oats, rye and barley. However, new research from Finland has found that coeliac sufferers can eat oats in moderate amounts without ill effect. This five-year study found that individuals with coeliac disease who ate oats were no worse off in terms of symptoms or nutritional status than those who did not. Contrary to conventional wisdom, oat-based muesli, oatcakes and rolled oats appear to be safe occasional options for coeliac sufferers.
