We have all heard about the benefits of taking antioxidant supplements, but in more recent years’ antioxidant supplements have also received occasional bad press. Although the reports of the benefits significantly outweigh the negatives, I thought it would be a good idea to better understand the arguments against the use of antioxidant supplements by speaking with Professor Alf Lindberg.
When I first raised the topic of some of the negative claims I’d heard about antioxidant supplements, Alf began by explaining that I must not think of supplements like pharmaceutical drugs, since most pharmaceutical drugs are based on purified chemicals with a single action. Take antibiotics for example – if you have an infection you take an antibiotic, which often only works on a limited number of bacterial strains. The antibiotic successfully kills the specific strain of bacteria leaving the rest of the microbial population unaffected.
Supplements are naturally-sourced compounds, which act in a variety of ways in our bodies. Antioxidants also differ greatly from one another so it is important to consider them each on an individual basis.
Alf and I discussed the following anti-antioxidant arguments especially with regard to taking supplements:
1) ‘Consuming one type of antioxidant (e.g., in a supplement format) can cause oxidative stress’ This argument may be scientifically sound in certain instances:
Tomato extract contains different natural antioxidants (lycopene, beta carotene and vitamin E). If one is converted into a free radical and becomes reactive, but less reactive [than the first]. It will then react with another, which will in turn be less reactive. All of them react with each other decreasing the damage that would be happening to our lipids, proteins and DNA. The anti-antioxidant argument is that if there is only one type of antioxidant present, (e.g., in a high-dose lycopene supplement), then there are no other antioxidants to provide that protective cascade effect. Then you could end up with a large amount of reactive lycopene, which itself can cause what they call ‘antioxidant stress’.’
Although the scientific theory is correct it does not mean that this is what actually happens in the body and unfortunately there are no suitable experimental animal models to test it. We recommend that our supplements are taken as part of a healthy diet and if possible with food as this improves the chances of absorption and will also negate the potential risk this claim raises.
Molecular theory supports the claim that consuming one type of antioxidant may cause ‘antioxidant stress’, however, this effect has not been demonstrated in an animal or human model and thus there is no evidence to test whether this is what would actually happen.
2) ‘High-dose antioxidant supplements can abolish the beneficial effects of exercise’ ‘Free radicals are a natural by-product of aerobic metabolism in the cells (energy production using oxygen), which ramp up during physical activity. The free radicals produced by this increase in metabolism signal the cell to make its own home-made antioxidants. These endogenous antioxidants are very important, and may be responsible for many of the health benefits associated with physical activity. If you therefore have high levels of a single antioxidant from a supplement, it can snatch up all the free radicals produced by exercise before they have a chance to trigger the synthesis of the beneficial endogenous antioxidants, which can also cause detriment to the other processes which rely on the endogenous antioxidants.’
In theory some antioxidants from supplements may ‘snatch up’ free radicals generated by exercise however, without an appropriate scientific model we just don’t know if this is true in practice.
The complex nature of our bodies means that a simplified molecular reaction in theory may turn out quite differently in practice and that reaction in turn could be different for each individual. In addition, not all antioxidants act in the same way. Curcumin, an extract of turmeric and the active ingredient in our Turmeric+ product (previously Ateronon Active), acts to reduce delayed onset muscle soreness without inhibiting the body’s muscle-growing response to exercise. It is therefore an ideal supplement to complement to an exercise routine.
3) ‘Large doses of antioxidants can prevent the body from detecting, and thus fighting, cancers in their early stages’ ‘The body’s natural damage-seeking protein p53 is inhibited by antioxidants, and so the natural process by which cancer might be stopped before it starts is disrupted’.
This argument was made in response to data from a mouse experiment. Although relatively available, mouse models are a poor substitution for human beings. ‘We can cure mice from diseases that they would otherwise never get in a non-laboratory setting but this usually has no reflection on what may happen if the same was tried with a human’ says Alf. ‘The mice used in laboratory experiments are usually homogeneous, which means they have been inbred whereas humans are heterogeneous’. It is best if possible to draw conclusions from studies with human participants, however, results in a laboratory setting are often very difficult to replicate in the real world.
Antioxidants have been claimed to play a role in the detection of cancers in their early stages but currently there is insufficient evidence to support this claim in humans.
4) ‘Antioxidants can all be got from your diet; supplements are only justified if you have a deficiency’ Another excellent claim, in theory. A comparable measure of whether or not an individual has a healthy diet is whether or not they get their 5-a-day of fruits and vegetables. I considered myself to be a healthy individual and my hopes were dashed when I recorded my intake of fruit and vegetables for a week and found that I only hit my 5-a-day once! I’m not alone, however, 64% of us in the UK are not getting our 5-a-day. So how about countries further north where the winters are severe and access to vegetables is even more reduced?
A Finnish study involving 1,031 men prospectively investigated the impact of lycopene levels in the blood on risk of having a stroke over a period of 12 years. The levels of lycopene in the blood of the men were assessed at the beginning of the study, and based on the amount of lycopene in their blood they were split into four groups. During the study there were 25 strokes in the 258 men in the low lycopene group and 11 strokes out of the 259 men in the high lycopene group. The study concluded that the risk of stroke was cut by 55% by having a diet rich in lycopene.
Another important factor to consider when looking at antioxidant use claims both for and against - is the quality of the data the claim is based on. The Finnish study was prospective, which means that the participants started the study and then were observed over a period. The alternative format to this is a retrospective study, which means that you start at the end and work your way back in time ie, in this case you would approach men who had both experienced and not experienced strokes and ask them what their diet was like in the last 12 years. A retrospective style study would introduce more bias and errors into the study data as if you had experienced a stroke you may be more likely to think that it was as a result of your dietary choices looking back.
5) ‘Antioxidants may increase the risk of lung cancer in those with an already higher risk’ ‘In 1996, a study of more than 18,000 men and women at high-risk for lung cancer looked at whether antioxidants could reduce their risk of lung cancer. Study participants included current smokers, former smokers, and workers with prior exposure to asbestos, who were randomized to receive beta carotene, vitamin A or placebo. The study was stopped early when preliminary results showed a 17% higher death rate in the antioxidant groups’.
The participants who received vitamins in the study were randomised to have either 15mg or 30mg of beta carotene and 25,000 IU of retinol per day. The recommended daily allowance of vitamin A for adults between 14 and 51+ years is approximately 800mcg. The participants receiving vitamin A in the study would have been receiving between 7515mcg and 7530mcg. Most drugs given at these concentrations would cause an adverse reaction, as highlighted earlier, supplements have multiple reactions in the body and therefore these concentrated levels are also bound to have less positive effects.
Alf explained that there is a therapeutic window of sensitivity for supplements in which a positive benefit can be seen. Ideally a supplement will have a large therapeutic window, which means that a positive benefit can be seen throughout a range of concentrations with more of a positive benefit being seen at higher concentrations within that range. A supplement with a small therapeutic window will have a small range of concentrations in which a positive benefit can be seen otherwise the supplement has no benefit or a less positive effect.
When Alf was growing up cod liver oil was the wonder supplement that parents and doctors evangelised. One tablespoon was the recommended allowance; however, some parents gave their children three tablespoons rationalising that if one was good three must be three times as good; we now know that you can have too much of a good thing.
Cambridge Nutraceuticals carries out its own research and also uses the recommended daily allowances of vitamins and our own research where applicable.
Conclusion Even when we have quality data, humans are multi-factorial and respond to vitamins and minerals in different ways; the clinical outcomes in the real world vary wildly from the results generated in a laboratory environment. We need to use the data we have but bear in mind its limitations when it is applied in the real world.
Health is not a disease you can treat with high concentrations of supplements; it is a long term goal that can be achieved with a combination of eating and living well with plenty of exercise as well as rest and supplementation where appropriate.