Some Frequently Asked Questions, first published in SAGA Magazine (13)
Professor George Lewith
I’m worried about using sunscreens as I’ve heard that some of the chemicals they contain may cause cancer. If this is true, what are the alternatives, apart from staying indoors?
If any of the major retail outlets that deal with sunscreens were selling products that might actually induce cancer, then all of us would be suing them for very substantial amounts of money, and the products would simply not be on the market; it would be a matter of self protection! I think we can say very clearly and definitely that current products sold to block sun burn and minimise skin cancer are, as far as we know at present, not carcinogenic. There may, of course, be some evidence that could emerge at some point in the future to suggest that this view is incorrect, but at the moment that there is no solid evidence suggesting sunscreens contain carcinogenic chemicals. Perhaps you may have got this confused; sunburn, or repeated exposure to sunshine without sun block, may actually cause skin cancer. Very often these skin cancers are just little “sun spots”, which can easily be burnt off or removed with very minor surgical procedures. However, occasionally you may actually get very serious nasty tumours, such as melanoma, which spread rapidly from the skin to the liver and many other parts of the body and are very deadly tumours. The reason why we use sunscreen, sun hats and sun protection is largely related to the increasing incidence of melanomas since the 1960s and 70s. Prior to that northern Europeans tended to expose far less flesh to the sunshine. Continued exposure to the sun, and particularly repeated sunburn, is very definitely a trigger for nasty cancers. My advice would be to continue to use sun blocks in a thoughtful and sensible way and certainly try hard to avoid burning. You needn’t stay indoors, and if you don’t wish to wear sun block then wear broad brimmed hats, long sleeved shirts, along with thin, long trousers, so that you can be cool and minimise exposure to the sun at the same time.
Do you know anything about a food supplement called Chlorella? A friend says it can clear pollution from the body and make the immune system more effective.
Chlorella is a green alga that is said to contain a very large number of concentrated micronutrients. It was thought in the 1940s to provide a wonderful answer to possible food shortages caused by population growth. There were many people who thought it might be a very promising primary food source and a solution to world hunger. It grows quickly and requires carbon dioxide, seawater and sunlight. Unfortunately, Chlorella in large volume proved much more difficult to produce than we at first thought. Chlorella is an alga and so is very rich in essential amino acids, the building blocks for protein that we all need to replenish our bodies. It also has a whole range of concentrated minerals, in particular zinc and magnesium, so it is a relatively cheap, high quality food product.
Over the last 50 years all sorts of claims of been made for Chlorella in relation to its “magical curative qualities”, as an essential extra food supplement. There is absolutely no evidence that it can clear pollution from the body, but it is a high quality food that would certainly be useful in undernourished individuals. As far as my searches have concluded, I can’t find any evidence that it can “make the immune system more effective”, but it is certainly safe and also an excellent non-meat based source of essential amino acids.
Is there any point in taking supplements containing omega 3 fish oils to treat depression?
Essential fatty acids form the main building blocks of all cells; they are actually part of the cell membrane. Cell membranes are particularly rich in omega 3 essential fatty acids, or fish oils. The brain, which is effectively a collection of nerve cells, is substantially made up of a carefully designed mixture of essential fatty acids interconnected by axons (stringy bits of nerves) or strands that are insulated by essential fatty acids. Therefore omega 3 essential fatty acids are very much part of the brain’s architecture and integrity, without them we simply don’t function terribly well. There is a therefore a good theoretical reason for thinking that behavioural disorders, such as depression, may well be influenced by essential fatty acid deficiencies and could possibly be treated by supplementation. The clinical trial evidence at the moment indicates that there are some studies that suggest that the addition of extra omega 3 essential fatty acids (usually a couple of grams a day) does help with a whole range of behavioural disorders, including depression. However, not all the studies are positive; the evidence is split. Some trials use quite low doses of essential fatty acids, well below the 2 grams a day recommended dose, and inevitably come to negative conclusions, while others that use adequate dosage regimes come to both positive and negative conclusions based on much the same sort of study. You usually need to use essential fatty acids for six to eight weeks before you see a clinical response, but some studies that have used adequate dosage regimes for prolonged periods, still come to negative conclusions. It seems that some people to respond to high dose essential fatty acids and their depression does improve, while others simply don’t respond. Many of the studies in this area have involved very small numbers of patients, so it is really quite difficult to come to any definitive conclusions at the present time. Essential fatty acids are pretty harmless to take, they are relatively cheap, and a three month trial is most unlikely to do you any damage. They can be used with conventional antidepressants and may (possibly) add to their effectiveness. If you are thinking of taking fish oils (that’s the omega 3s) then my advice would be to go ahead and try it. You can’t do any harm and the evidence suggests that it may be quite useful.
I’m convinced that I developed type 2 diabetes as a result of stress – family illness combined with work and money worries – but my doctor disagrees. What do you think?
It is quite possible that during periods of great stress you may eat inappropriately, put on weight and burn up quite a lot of micronutrients. Type 2 diabetes is thought to be related to at least some of these issues, particularly if you have an underlying genetic vulnerability. If you are slightly overweight but go through a period of great stress, over six or nine months, you might increase weight, diminish exercise and tip yourself over into diabetes. Perhaps your doctor is thinking that the stress caused by family illness, work and anxiety is “the trigger” – chronic illness is rarely that simple. There is usually an underlying genetic or familial predisposition, some unhealthy factors in your lifestyle and something that just “tips the balance” and begins the actual disease process. I tend to think you are right, in that you are seeing the evolution of this chronic long term problem as being triggered by a period of sustained worry and anxiety. I suspect the same can occur with almost any chronic condition.
My daughter wants me to try something called the Buteyko method to help my asthma – does it work?
The Buteyko method is one of the many approaches to breathing retraining that are currently available to asthmatics. There have been studies on both Buteyko and yoga, but unfortunately, as so often happens in complementary medicine, the majority of these studies are small and have fundamental methodological flaws. Sometimes it is very difficult to produce a placebo or controlled intervention in yoga or a controlled breathing techniques, such as Buteyko. Many people may know about Buteyko simply by looking it up on the web, even though they may be randomised to what appears to be a convincing placebo, they may “cheat” with their treatment quite innocently subverting the placebo intervention. Furthermore, we don’t really know what is effective in the Buteyko breathing technique; is it the attractive physiological theories that surround the controlled breathing techniques used by Buteyko teachers, or is it simply the act of the individual being aware and concentrating on their breathing, rather than just taking another asthma inhaler.
The evidence that we have available from the few trials that have been published, suggest that Buteyko may well help. Some very dramatic and encouraging case reports have occurred and people claim to have been able to “throw away” their asthma inhalers. There have been no reports of harm, but hard evidence that the Buteyko technique itself has some inherent validity and some specific effectiveness, is currently unavailable. Acute asthma is often associated with considerable degrees of anxiety and fear, which is not surprising if you suddenly find you can’t breath! If using a Buteyko approach can give you some control over your anxiety, and the understanding that you can manage your breathing and not panic because you have trained yourself to do it must be helpful. You should not stop your conventional asthma treatment without consulting your GP, and if you are particularly worried about your breathing you should certainly be guided by your peak flow, respiratory function and your previous experience of asthma. Don’t just rely on the Buteyko technique if you think you have an acute asthma attack and may be getting into respiratory difficulty. Acute conventional treatment for severe asthma attacks can be life saving.
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