Past event: Soy & Health 2008
5th International Conference Soy & Health joined with the 1st International Symposium
Soy & Strategic Marketing
200 delegates from around the world visited the beautiful city of Ghent, Belgium from 2-3 June 2008 to
attend the 5th International Conference Soy & Health 2008 and the 1st International Symposium Soy & Strategic Marketing. Poster abstracts covering a range of scientific topics related to soy were on also display .
Highlights from the scientific symposium, Soy & Health 2008, are provided below.
Soy, cholesterol lowering and cardiovascular disease
New insights into the involvement of soy protein in cholesterol lowering were presented by
Dr Maria Rosa Lovati (University of Milano, Italy) whose research suggests that the predominant hypocholesterolemic activity of soy protein is from bioactive peptides (not isoflavones) which
may ultimately have implications for potential drugs for hypercholesterolemic patients and in the
development of functional foods. Dr Gerald Rimbach (Christian Albrechts University, Germany)
presented evidence that isoflavones significantly affected the expression of genes that encode
for proteins involved in vascular tone. Genistein also reversed homocysteine and oxidised LDL- induced alterations
of protein profiles and prevented apoptosis. In addition, sulfation of isoflavones, which masks important hydroxyl
groups on the isoflavone molecule, could decrease their impact on endothelial function. Prof Giovanni Mann (King’s
College, London, UK) provided information on the molecular mechanisms by which estrogens, isoflavones and
polyphenols activate signalling pathways involved in endothelial nitric oxide release. A soy protein rich diet maintains
low blood pressure and antioxidant gene expression and a diet rich in soy isoflavones during gestation and adulthood results in decreased oxidative stress, improved endothelial function and reduced blood pressure in vivo. As part of a larger study on osteopenic, postmenopausal women, Prof Francesco
Squadrito (University of Messina, Italy) (left) showed that 54mg of genistein plus calcium, vitamin D3
and a healthy diet was associated with favourable effects on both glycemic control and some cardiovascular
risk markers in osteopenic postmenopausal women.
Isoflavones and other soy components
Dr Elvira de Mejia (University of Illinois, Urbana-Champaign, USA) suggested that soy protein hydrolysates inhibit the enzymes involved in leukaemia cell viability and may, therefore, have anti-cancer potential. Research by Dr Guy Haegeman (Ghent University, Belgium) suggests that soy isoflavones can selectively block the activation of specific target genes, such as interleukin-6, which is involved in chronic inflammatory disorders, diseases of age and tumorigenesis. Prof Kenneth Setchell (University of Cincinnati, USA) provided data on the potential usefulness of a soy isoflavone enriched pasta containing 33mg of isoflavones as a therapeutic tool for the reduction or relieving of symptoms associated with diabetic gastroparesis. In Type 2 diabetic patients with documented delayed gastric emptying the inclusion of the isoflavone enriched pasta in the diet led to a significant acceleration in gastric emptying and to normalisation of delayed gastric emptying. Importantly postprandial serum glucose and insulin levels were not adversely affected. In a separate study to investigate possible mechanisms the research showed that the expression of 58 genes were significantly affected by the the presence of isoflavones in pasta and these included classes of genes involved in gastric function and oxidative stress. Prof Willy Verstraete (Ghent University, Belgium) focused on the microbial and dietary factors associated with the equol producer phenotype in healthy postmenopausal women. During a 5 day treatment period 3 portions of either soymilk or soy germ containing 28.5 and 38mg isoflavone aglycone equivalents per portion respectively were given daily. Analysis of the urine samples showed that bioavailability of genistein and daidzein in soymilk was significantly higher than in soy germ tablets. The strong equol producer phenotype correlated negatively with Clostridium coccoides-Eubacterium rectale counts and positively with sulfate-reducing bacteria. Those with higher PUFA and alcohol intake were more likely to be strong equol producers.
Metabolic syndrome, obesity and diabetes
Dr Leila Azadbakht (Isfahan University of Medical Studies, Iran) (right) presented data on the possible therapeutic
effects of soy nut and soy protein consumption on insulin resistance and markers of cardio-vascular risk
in postmenopausal women with metabolic syndrome. Improvements in lipid profile, inflammatory indices and
markers of oxidative stress suggest that soy nut consumption may reduce cardiovascular disease. Decreasing
insulin resistance also indicates that soy consumption may play a role in preventing diabetes. Soy nut consumption
is more effective than soy protein. The fat and fibre content of soy nuts may be responsible for this.
Prof Stephen Atkin (University of Hull, UK) provided new data on the dietary isoflavone
effects on insulin resistance and cardiovascular risk factors in type 2 diabetes and subclinical
hypothyroidism. In postmenopausal women with type 2 diabetes his research showed that, after 12 weeks, soy protein consumption (30g/day containing 132mg/day isoflavones) resulted
in significantly lower mean values for fasting insulin, insulin resistance, glycated haemoglobin,
total cholesterol, LDL cholesterol, and cholesterol/HDL cholesterol ratio. No significant change
occurred when the study was repeated with 132mg of isoflavones alone. In another study in
patients with subclinical hypothyroidism, insulin resistance and systolic and diastolic blood pressure fell significantly using a 16mg of isoflavones in 30g of soy protein preparation. In
a 2mg preparation only systolic blood pressure fell. Thyroid function was unchanged. In her
presentation Dr Janice Harland (HarlandHall, UK) presented the results of a meta analysis of studies conducted in overweight and obese subjects which showed that cholesterol, specifically LDL cholesterol, was
significantly lower when 18-43g soy protein was included in the diet. This confirms that that soy protein is at least
equivalent to animal protein in weight-reducing regimes, but also that it reduces one of the markers of cardiovascular
disease thereby reducing the the risk of one of the major complications associated with obesity.
Dr Mark Messina (Loma Linda University, US) (left) presented data from a meta analysis of studies investigating the effects of soy protein and isoflavone intake on total and free testosterone levels in men. Peer reviewed studies in English were selected which included adult men who consumed soy foods, soy protein isolate, or isoflavone extracts (from soy and red clover). All studies included assessments of circulating testosterone, free testosterone, sex hormone binding globulin or calculated free androgen index. The results showed that, regardless of statistical model, neither soy protein or isoflavone intake had any significant effects on these measurements. Prof Francesco Squadrito, (University of Messina, Italy) is involved in long term study of postmenopausal women investigating efficacy of genistein on bone health. Previous findings have shown that 54mg/day of genistein aglycone positively affects bone metabolism in women and after 36 months genistein continues to show positive effects on bone formation in this cohort of osteopenic postmenopausal women with significant increases in bone mineral density at both femoral neck and lumbar spine regions compared to the placebo. Research by Dr Peter Celec (Comenius University, Slovak Republic) provided further insight into the complex topic of cognition and mental health. There are very few studies on the role of soy isoflavones and the results published so far are conflicting. His own research, looking at differences between men and women and the effects of testosterone suggests that soybean intake may improve spatial cognitive abilities which may be mediated by endocrine changes which are gender specific. In his presentation, Prof Jean Daydé (University of Toulouse - Ecole d’Ingénieurs de Purpan, France) provided information on soy saponins, their bioavailability and their role as healthy micronutrients. Their beneficial effects include hypocholesteremic and antioxidant activity, hepatoprotective and antiviral properties, as well as anticarcinogenic activities. However, more studies are needed on the biological effects of soy saponins, and their additive, synergetic or antagonistic effects with isoflavones need to be clarified.
Dr Jean-Michel Lecerf (Institut Pasteur, France) summarised the practical information about soy foods that should be provided to patients and physicians. This included information on composition and function so that doctors are informed about which products may be useful for patients with particular diseases or conditions e.g. heart disease, diabetes, lactose intolerance. Dietary advice, recipes ideas and information on the types of soy foods available was also invaluable for dietitians who give practical advice to patients. Lynne Garton (Alimenta, London, UK) (right) focused on the role of health professionals in recommending soy, how to recognise soy foods, tips to help overcome barriers to consumption and practical suggestions to help patients consume soy rich diets.
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