Availability, flavour of soy should provoke greater use
white paper that reviews literature and studies investigating the
health benefits they may confer.
The paper was authored by Shannon Koski, manager of protein applications at US protein manufacturer Protient, part of Associated British Foods (Ingredients).
According to Koski, increased consumer acceptance of soy is down to growing awareness of its use as a healthy ingredient. That, in turn, is leading retailers to reorganise their shelves to make room for soy products.
Market analyst Mintel also thinks the take-up of soy products may be down to the 'free-from' market, as soy milk is gaining a share of the dairy-free market.
It valued the UK dairy-free market at £32m in March, with sales of products such as soy milk and yoghurts growing by 28 per cent over the last three years.
"The popularity of soy milk under high-profile brands has certainly played its part in catapulting the free-from food sector into the mainstream away from the specialist dietary food field," said consumer analyst Julie Sloan.
"The healthy attributes of soy have been linked to the isoflavones naturally occurring in soy in conjunction with the soy protein," wrote Koski. Her paper focuses on soy meal, flour, concentrates and isolates, as these have been shown to result in the most health benefits.
It looks at positive studies that point to benefits in a number of areas: women's health; heart health; bone health; muscle mass; and prostate health.
For women's health, it is thought that soy isoflavones may exert oestrogenic effects, making them a suitable alternative to hormone replacement therapy for women dealing with symptoms of menopause, such as hot flushes.
As well as citing a studies that showed a 30 to 40 percent reduction in symptoms in intervention studies using soy foods, soy protein isolate and soy extracts providing between 30 and 100mg of isoflavones per day, the paper also considers epidemiological data that suggests an inverse association between phyto-estrogens and breast cancer risk, but not a strong one.
Based on data from a Chinese and Asian-American studies, Koski wrote: "It appears that soy phyto-estrogens are cancer protective, particularly when consumed early in life."
However a recent meta-analysis study published in this month's Journal of the National Cancer Institute (Vol. 98, pp. 459-471) was not considered. After pooling 18 epidemiological studies (12 case-control and six cohort or nested case-control) dating from 1978 to 2004, researchers from Georgetown's Lombardi Comprehensive Cancer Center in the US concluded that the data on breast cancer risk reduction was inconclusive.
In particular, they said that women should choose soy foods over supplements as they long term effects of high-dose supplements are not know - advise that was criticised by the National Nutritional Foods Association as "irresponsible and misleading".
In the case of prostate health, the author said there is limited epidemiological data to indicate a link between soy intake and reduced risk, but a pilot intervention study has suggested that isoflavones may be of benefit.
"For several reasons, men concerned about their prostate health may consider incorporating soy into their diets."
Heart health and soy is an area that has been studied rather more thoroughly, and the paper explains that soy product consumption has been seen to reduce levels of total cholesterol and LDL cholesterol, as well as improve plasma lipids. Soy isoflavones are seen to reduce low density lipoprotein oxidation and improve vascular reactivity.
Koski said that a large-scale Chinese study (Journal of Nutrition Sept 133: 2874-2878 (2003) "provides direct confirmation that soy food consumption may reduce the risk of coronary hear disease".
In 1999 the US Food and Drug Administration approved an unqualified health claim linking consumption of soy foods to a reduced risk of coronary heart disease. According to a 2000 report in FDA Consumer, consumption of soy foods increased 20 percent per year since 1995 and the approval of this claim led to surging interest.
For bone health, the paper said that the clinically important benefits of isoflavones are "suggestive but not conclusive, and more research is needed in this area". For muscle mass, it sad that soy is an important protein source for improved mass, "and potentially for improved antioxidant activity as well".
Koski concluded: "Given the increasing number of products containing soy, and the improving flavour of such products, soy foods should be incorporated into the diet of most adults for their numerous health benefits."
The white paper, which did not discuss any potential negative effects of consuming soy, comes just a month after an independent panel of scientists convened to review recent scientific data on the soy compound genistein and assess whether it could have a negative impact on human development or reproduction.
After three days of discussion, the overall consensus was that, when given orally, there was no threat from the reproductive and developmental effects of soy. The effects of genistein in relation to heart disease or cancer risk, for example, were not explored by the panelists.
Nor was the panel's decision unanimous: one panel member disagreeing with the finding and saying that greater caution was merited.
To receive the full white paper please email Chris Pope at Words in Motion.
