There is “insufficient” evidence to show that soy isoflavones can benefit bone health and ease menopausal conditions, according to the European Union’s central science agency.
Responding to the menopause rejection, the European Natural Soyfoods Manufacturers Association (ENSA) said it was surprised and disappointed by the European Food Safety Authority (EFSA) position, arrived at, “despite a large amount of scientific evidence.”
“ENSA is disappointed EFSA did not acknowledge the health benefits of soy isoflavones,” the group said, noting further data had been sent to EFSA after the initial rejection in July, 2011, as part of a reconsideration process for claims that had been delivered “insufficient data” verdicts.
Hot flash in the pan?
“We are all the more surprised by the [latest] conclusion of the EFSA since a very recently published meta-analysis by Takushowed that soy isoflavones are effective in reducing the frequency and severity of hot flashes,” ENSA continued.
“This meta-analysis comes on top of numerous studies which have shown the health benefits of soya for women going through menopause. Women who do not like to use hormonal therapy to reduce the symptoms associated with menopause often try more natural ways to reduce hot flushes. Soy which naturally contains isoflavones has been used since many years by many women.”
“Soy foods as part of a healthy diet are still a good choice for women going through menopause since they are a good source of high quality vegetable protein and are low in saturated fat.”
A spokesperson said EFSA-approved claims already existed for low saturated fat levels and cholesterol management that soy could utilise, along with protein content and bone health.
“Soy foods manufacturers will continue promoting the nutritional and health benefits of soy foods, in compliance with the applicable legislation,” the group said.
EFSA’s Panel on Dietetic Products, Nutrition and Allergies (NDA) previously rejected the ability of soy proteins and isoflavones to help maintain healthy cholesterol levels, despite similar claims being approved in more than 10 countries, including the UK, Japan and the US.
Now it has kyboshed bone health and menopause under the article 13.1, general function section of the EU nutrition and health claims regulation (NHCR), although the “insufficient” verdict may leave the door open for further submission under the proprietary and emerging science, article 13.5 avenue.
ENSA said the industry was as yet undecided about whether it would pursue such a course of action, but was scrutinising the opinion in detail.
Maintenance of bone mineral density
For the bone health claim, the NDAfound 14 studies did not show soy isoflavones could benefit bone mineral density.
It said only two studies among menopausal women with osteopenia or osteoporosis showed a benefit in the spine and neck at soy isoflavone doses of 54 mg/day. The other 12 studies, despite employing dosages as high as 200mg/day, showed no significant effect.
That aside, the NDA did acknowledge that the other studies, “provide some evidence for an effect of soy isoflavones on the attenuation of bone mineral density loss”. But the sum of evidence was “weak” and so it delivered its “insufficient” conclusion.
Thirteen randomised clinical trials (RCTs) were submitted to demonstrate the ability of soy isoflavones to help reduce menopausal vasomotor symptoms, six of which the NDA said showed statistically significant reductions in hot flushes.
Six others did not, and one did not report hot flush results.
Of the studies that showed a benefit, the NDA said, “most of these RCTs were at high risk of bias due to major methodological weaknesses in the statistical analyses performed (e.g. inadequate handling or no consideration of missing data, repeated measures and/or multiple comparisons not taken into account, analysis of data with a high risk of not being normally distributed by parametric tests without verification of the assumption of the statistical test applied), and/or that data were inadequately reported.”
It said most of the studies, “were at high risk of bias”.
The NDA opinion can be found here.
The other groups that have worked with ENSA on the submission of some of the claims and data are the European Vegetable Protein Federation (EUVEPRO) and the UK Soy Protein Association (SPA).
Soy-cholesterol lowering claims are also approved in South Africa, the Philippines, Brazil, Indonesia, Korea, Malaysia and Turkey.