Regarding scientific research and other important health information, the most difficult attributes to ferret out, but which are fundamental, underlying the information's reliability and integrity, are who is reporting the information, what is their independence or commercial links or sponsorships, and any ulterior agenda which may underlie the announced information.

In these days of political spin and counter spin, what may at first glance appear to be an obvious and factual report may in reality turn out to be more convoluted and complicated.

The scientific and medical literature is full of examples of such 'alerts', including the dangers of taking antioxidant vitamins such as beta-carotene, the notion that vitamin C causes cancer, or as more recently announced by the media, heart disease.

Evelleen Richard's fantastically eloquent book Vitamin C and Cancer – Medicine or Politics (MacMillan, 1991) laid out the holy grail of who really controls which research is believed, in a gripping battle between Linus Pauling (now deceased) and Charles Moertel of the Mayo Clinic over vitamin C's reputed ability to prolong life and alleviate symptoms in Cancer patients.

Their very acrid public correspondence demonstrated, sadly, that the same rules don't apply to all the fish in the sea. The Mayo Clinic reputedly replicated Linus Pauling's clinical trial using 10g of vitamin C for cancer patients. Unfortunately, the trial only lasted a few months, and then the vitamin C was abruptly withdrawn; however, the Moertel side were able to publish that vitamin C didn't have the reputed beneficial effects for cancer. This flawed research is still often repeated in the literature, and vitamin C is still often portrayed as a 'useless waste of urine' by many doctors.

Recently there have been several other 'scares', including the dangers of beta-carotene for smokers, as well as the dangers to all of us from soy. Both of these subjects are huge areas of research, much of it extremely complex and convoluted.

Regarding the beta-carotene issue, a comprehensive review of the scientific literature and the clinical and epidemiological evidence looked at in the round demonstrates that beta-carotene does not increase the risk of lung cancer to smokers, full stop.

The soy controversy also appears complex. Please read for yourselves the comprehensively referenced article Tragedy and Hype – The Third International Soy Symposium by Sally Fallon and Mary Enig, Ph.D. in Townsend Letter for Doctors and Nexus Magazine. The authors outline several serious areas for concern about the widespread consumption of soy in our diet – as a meat substitute, as a milk substitute, as infant formula, and as isolated isoflavones for the alleviation of menopausal symptoms. (see also www.soyonlineservice.co.nz and www.westonaprice.org)

Unfermented soy contains a number of natural toxins, including enzyme inhibitors which block protein digestion, are growth inhibitors and goitrogens, substances which depress thyroid function. Soybeans are also high in phytic acid, which can block the uptake of minerals such as calcium, magnesium, copper, iron and zinc. Many of these toxins can be removed or mitigated either by cooking, fermentation, and by eating sufficient meat and fish products to counteract the high phytate content of soybeans. The authors also raise questions regarding the safety of the mildly oestrogenic isoflavones and worry about anticancer claims (i.e. that soy reduces cancer risk) being made for soy.

Not having personally read the voluminous literature regarding soy (and that is what it would take for me to form my own reliable opinion), and in my quest for guidance around an exceptionally important issue, I am still engaged in scientific consultation. There appears to be a significant body of opinion supporting soy's benefits in cardiovascular health, particular its ability to significantly lower cholesterol levels.

There is also conflicting research evidence and opinion regarding the phytoestrogen component of soy and its potential benefits or otherwise for hormonal issues, including fertility, breast cancer and menopausal symptoms.

I now return to the nub of this dilemma, where 'respected' experts argue both sides of the question. Whom do you believe? Probably both sides are correct to a certain degree; wouldn't it be preferable that in this critical issue of what we eat, that both sides work together to seek the truth rather than become even more polarized?

Perhaps we all need a sabbatical to plough through all the research papers; however, almost certainly more research will be required to answer these unique questions relating to our health posed by soy.