New project documents vanishing heritage diets for future health benefits

The world's 'heritage' diets could hold vital clues to better health. Writing in Nature Medicine, researchers from 12 countries have launched the World Diet Initiative, a global effort to document and study these diets before this knowledge is lost.

People around the world have practised distinct diets for thousands of years. Maasai communities in East Africa are known for diets rich in animal products such as milk, meat and blood. In Ethiopia, diets are largely plant-based, featuring pulses, vegetables and grains, often fermented. Indian meals draw on a rich array of spices, while across the Pacific, fish, taro and coconut are commonplace.

These heritage diets have developed over generations, shaped by the foods available in the local environment and the ways they are prepared. In some communities that still follow heritage diets, chronic illnesses such as diabetes and cardiovascular disease have historically been less common.

Dietary diversity is disappearing fast

Heritage diets around the world are being replaced by uniform 'Western-style' diets featuring the same industrially processed foods. As these diets disappear, so too does a precious opportunity to understand how they shape human health.

The World Diet Initiative aims to close this gap through two components:

• The World Diet Atlas will map heritage diets worldwide, detailing the foods and how they are sourced, prepared and eaten. It will be a freely available resource for researchers, policymakers and communities.
• The World Diet Project will study the biological effects of these diets, using consistent methods so findings can be compared across populations.

The initiative will operate as a global consortium. Local partners will lead research and retain ownership, with findings shared responsibly with researchers around the world.

Changes within two weeks

Recent work by some of the initiative's founders offers a glimpse of how studying heritage diets can reveal new insights into how foods shape health.
In a trial in the Kilimanjaro region of Tanzania, men who swapped their local heritage diet, rich in legumes, whole grains and fermented foods, for a processed, Western-style diet showed increased inflammation and other biological changes linked to chronic disease within just two weeks.
Those who switched the other way, or drank a traditional fermented millet-and-banana drink, showed changes in the opposite direction, including reduced inflammatory markers.

Not a blueprint for healthy eating

The researchers stress that the initiative is not a nostalgic call to return to past ways of eating, nor a claim that heritage diets are always healthier. The point is that these diets act on the body, the immune system, metabolism and microbiome, in strikingly different ways, and each has something to teach us.

These diets are not a blueprint for healthy eating, but they are biologically and culturally unique. Food influences our health in many ways and plays an important role in preventing disease. With the World Diet Initiative, we are now building the infrastructure to capture this knowledge and translate insights from heritage diets into health benefits for people worldwide - from preventing chronic diseases to better understanding how nutrition shapes immune function and vaccine responses."

 Quirijn de Mast of Radboud university medical center, co-lead of the initiative