I have been vegan for 4 years and I realise that I don’t know so much about soya. I hear criticism and I see that “free from” soya products are very trendy even in vegan fair-trade markets. Would soya, the cornerstone of vegan food, be detrimental to health and to the environment?
I raised the question to Hervé Berbille, an agro-food engineer expert on soya in human diet. Here are his answers.
Would you please introduce yourself and tell us why you have developed such a passion for soya? Do you have any connections with the soya industry?
My interest in soya is related to my specialisation in infant nutrition. Early on, I became convinced that, when breastfeeding is not possible, soya-based infant formula is the best alternative. Social perception of soya is terrible especially for infant feeding; a little detour on the Internet is enough to be convinced. However, if we stick to scientific literature (and people should stick to scientific literature…), no risk, including long-term risk, has ever been established (1).
In contrast, the emerging field of epigenetics leads us to think that early exposure to soya activates anticancer genes, ultimately conferring a kind of anti-cancer immunity. A recently published study shows that early exposure to soya could also prevent osteoporosis. Conversely, it is assumed that exposure to cow’s milk in infancy increases the risk of diabetes (2) and the subsequent risk of colorectal cancer (3).
However, it is the infant formula based on cow’s milk that is prescribed as first-line, and infant formula based on soya, which is subject of all suspicion.
I have no relationship with the soya industry; I never practiced my profession in this field.
Personally, I am part of the French tradition of “soyaists”, a school of thought, quite informal, which understood in the nineteenth century that the introduction of soya in food would be a factor in social progress and emancipation. I think this is still a valid opinion. People can blame my idealism, even my naivety, but certainly not my disinterestedness. This gives me absolutely nothing financially speaking, but this knowledge about soya is personally rewarding.
Before talking about the impact of soya on health and the environment, would you please introduce soya in a few words. Where is it from? In what form do we find it? Is it a seasonal plant?
Cultivated soya bean, Glycine max, Fabaceae family (peas, lentils, beans, etc.), comes from the domestication of Glycine soya, with smaller seeds, black coloured, in all likelihood originated in China, where it was grown more than 9000 years ago. Soya is an annual plant, meaning that there is only one harvest per year.
What are the nutritional characteristics of soya? Tofu comes in lots of different forms in food, fermented or unfermented. Is there a better way to eat it? Is there any danger in consuming it too much?
I personally prefer the unfermented soya (tofu, soya milk, textured vegetable protein) or that processed with a brief fermentation like lactic fermentation (yogurt, cheese), or even like the tempeh (fermented by a fungus). Further fermentations, such as those necessary to obtain miso and shoyu (soy sauce), can potentially generate carcinogenic compounds (carbamates).
There is no threshold exposure dose for soya. Of course we should not feed exclusively with soya, however, I’m still adamant that there is no possibility for any diet to reach a threshold presenting any risk to health, whatever your age (new-born), sex, health. Regarding women with breast cancer or in remission. Respectively, it is clear that eating soya increases chance of survival and reduces the risk of recurrence (4).
We talk about cancer, cardiovascular disease, allergies, risk for menopausal women. What are exactly the issues? Are some of these criticisms right? Why is soya so criticised?
For breast cancer, studies are now clear, and all converge: soya prevents cancer, reduces the risk of recurrence and improves therapy effectiveness… I am convinced that if soya isoflavones were simply called “flavonoids”, instead of “phytoestrogens”, these controversies simply would not have occurred.
An anecdote about this, recently, a team of researchers compared the testosterone levels between male soya consumers and male meat consumers. Surprisingly, testosterone levels were lower in meat eaters. Yet without going further into detail, the scientific data already available made these conclusions as logical and predictable. This is to explain that the bewilderment induced by the connoted term “phytoestrogen” even influenced the scientific community. This suggests its impact on the general public. However, in practice, the term “phytoestrogen” leads to a misinterpretation, these flavonoids protect us against the oestrogen produced by the body, which is very harmful.
Greenpeace and CorpWatch accuse soya producers of contributing to deforestation of the Amazon rainforests, what do you think? Can the large-scale soya growing be a sustainable substitute for meat?
These accusations are well founded, as long as it is specified that soya devouring the Amazon ecosystem is almost exclusively produced for livestock feed… Moreover, this accusation is ambivalent, suggesting that soya would be endowed with will, deciding on its own to leave its native China to go devastating the Amazon ecosystem … in fact, this awkward formulation hides the true responsibilities, namely human appetite for meat and dairy products, solely responsible for this environmental disaster. It is interesting that in France, the number one soya importers are by far Danone, Lactalis and Sodiaal, multinational companies specialising in dairy products … (5)!
In Europe, soya-based food for human consumption comes from soya grown in Europe, mainly from Italy and France, although there are unfortunately a few black sheep importing their soya from Brazil, but they are a minority, and without significant economic weight.
I read that soya production, about 80%, was derived from GMO. The transgenic cultivation is prohibited in France, but the import of food products from GMO is still possible. Is the use of GMO for large-scale soya cultivation inexorable and so damaging?
Yes, but again, this transgenic soya, imported as a meal, meaning as a protein concentrate, is for livestock feed. The cultivation of GM soya is strictly prohibited in Europe as you remember it rightly: paradoxically, it is by consuming meat and dairy products that we are exposed to GMOs, not by directly consuming soya … so the best way to protect ourselves from exposure to GMOs remains to consume soya, but well chosen, grown in Europe, and if possible organic. It must be understood that GMOs are expensive technology to develop, which require a substantial return on investment. In other words, without crop massification induced by animal feed, it would be difficult or impossible for multinational seed companies to obtain a return on investment on this technology. Also it should be noted the inconsistency of being against GMOs while consuming meat and dairy products, without which GMO technology is not economically viable…
What are you doing now and what are your plans for the coming months?
I am writing my book about soya, a long-term task.
I am often accused of running for the “soya lobby.” If it were the case, the famous lobby is not very powerful, because, in France, I am the only person defending soya (I say “defend” and not “promote” as defending soya leaves little time for its promotion…). My aim is to “vegetalise” food, “humanize” soya, nothing else other than as it was in its origins; feeding humans, as has been common practice in Asia for ages, that is it. Finally, as I repeat tirelessly, the “integrated” soya industry has no economical interest in people eating soya – directly. This “integrated system” combines soya production with its final goal, animal feeding. So, the direct consumption of soya, without going through animals, would inevitably lead to its own demise, so powerful and dominant is the “integrated system” today.
However, this would ultimately be beneficial to a local and diversified agriculture of soya. Soya farming for human consumption is almost always performed on small farms practicing crop rotation (soya, wheat, sunflower, etc.). Consuming soya directly also leads to a more socially and environmentally virtuous production.
Do you have readings or websites to recommend if we want to increase our knowledge about soya and while we are waiting for the release of your book?
Without hesitation, the site of William Shurtleff, the greatest specialist of soya, and his authoritative books; the site dedicated to nutrition, www.lanutrition.fr, and some scientific journals such as the American Journal of Clinical Nutrition …
(1) Strom BL1, Schinnar R, Ziegler EE, Barnhart KT, Sammel MD, Macones GA, Stallings VA, Drulis JM, Nelson SE, Hanson SA. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA. 2001 Aug 15;286(7):807-14.
(2) Virtanen SM, Räsänen L, Ylönen K, et al. Early introduction of dairy products associated with increased risk of IDDM in Finnish children. Diabetes. 1993;42:1786–1790
(3) van der Pols JC1, Bain C, Gunnell D, Smith GD, Frobisher C, Martin RM. Childhood dairy intake and adult cancer risk: 65-y follow-up of the Boyd Orr cohort. Am J Clin Nutr. 2007 Dec;86(6):1722-9.
(4) Messina M. Impact of Soy Foods on the Development of Breast Cancer and the Prognosis of Breast Cancer Patients. Forsch Komplementmed. 2016;23(2):75-80.