Scientific evidence can now include “causal relationships” suggested in observational or epidemiological studies, animal and laboratory experiments, generally accepted authoritative information validated over time, and traditional knowledge and experiences of use. The acceptance of these alternative ways of knowing came after years of lobbying by the health foods and dietary supplement industry.(emphasis added)
Basically, because pesky science was getting in the way of profit margins, now there doesn't need to be scientific proof that certain foods or supplements help prevent disease, there just has to be a "credible" claim. Sandy at Junkfood Science breaks it down, and sums up:
In other words, this gives an NGO, such as a health food or supplement industry organization, the ability to can make any claim it chooses and say it’s substantiated.
Few consumers will realize when they see a health claim on the label of a food or supplement, purportedly supported by scientific evidence from the WHO, that the definition for scientific evidence has changed.
Why has this story not been widely reported in mainstream media or in professional publications reaching the scientific and medical communities? It would appear the input of scientists and doctors in health policies is not wanted, as the WHO and UN-FAO become influenced by things other than the best science.
We have enough issues with food science and knowing what is actually good, and what foods have an actual effect on health issues or are preventative, without having to worry about what scientific evidence actually consists of.