Life Science

lifescience

Viva! Health dissects the latest scientific research and makes it easy to understand. Here we update you on recent findings…

BY DR JUSTINE BUTLER, HEAD OF RESEARCH, VIVA!

Climate change

Central Asian deserts spread

As global temperatures rise, deserts in Central Asia have spread north by as much as 100 kilometres, according to new research. Scientists found that since the late 1980s, temperatures have risen across Central Asia, including parts of China, Uzbekistan, Kyrgyzstan and Kazakhstan. Mountain regions have become hotter and wetter, accelerating the retreat of glaciers and these changes threaten ecosystems and those who rely upon them. Human activities such as mining and agriculture contribute to desertification. This research suggests that governments in Central Asia, and the rest of the world, should focus on sustainable farming.

Guglielmi G. 2022. Climate change is turning more of Central Asia into desert. Nature. Epub ahead of print.

THE FuTuRE iS FunGi

…swap beef to save the forests

Replacing just 20 per cent of the world’ s beef consumption with microbial protein, such as Quorn – a protein derived from fungi –could halve deforestation over the next 30 years, according to the latest analysis. It would reduce future increases in global pastureland and cut deforestation and related CO2 emissions in half, whilst also lowering methane emissions. Deforestation, of course, also devastates wildlife.

“The food system is at the root of a third of global greenhouse gas emissions, with ruminant meat production being the single largest source ” said Dr Florian Humpenöder, who led the study. The protein quality of microbial meat is equivalent to beef but requires 90 per cent less land and water and produces 80 per cent less greenhouse gas emissions.

Humpenöder F, Bodirsky BL, Weindl I et al. 2022. Projected environmental benefits of replacing beef with microbial protein. Nature. 605 (7908) 90-96.

Diet change

Crucial to protect biodiversity

Biodiversity loss is a threat to humanity but is often overlooked when considering the environmental impacts of diet. A recent study estimated the biodiversity impacts of five different diets in the US, estimating how many species would die following the widespread adoption of each diet. It also considered the impact of halving food waste in all five scenarios.

Not surprisingly, the meat-heavy, traditional US diet was catastrophic, condemning 200 species to extinction, 80 of them outside the US. Reducing food waste would save only 25 species. However, the worst diet of all was the Mediterranean diet, which would increase extinctions to 240 species because of greater cattle production for higher dairy consumption. In addition, more land would be needed to grow grain to feed farmed fish.

Best diets were the vegetarian and Lancet Planetary Health diets, which led to 30 per cent fewer extinctions, largely because less pastureland for livestock would be needed. Reducing food waste on these diets would halve the overall biodiversity footprint. Lead author, Dr Quentin Read, did not include a vegan diet in the study but said that he believes the results would have been better if he had.

Read QD, Hondula KL and Muth MK. 2022. Biodiversity effects of food system sustainability actions from farm to fork. Proceedings of the National Academy of Sciences USA. 12, 119 (15) e2113884119.

Vegan diet for weight loss and lower blood sugar

Vegan diets can help people who are overweight or have type 2 diabetes to lose weight and lower their blood sugar levels, research suggests. A review of 11 studies involving almost 800 adults compared the effects of a vegan diet with other diets on what’ s termed ‘ cardiometabolic risk factors ’ , such as body weight, BMI, blood sugar levels and cholesterol. They found that compared with other diets, following a vegan diet for three months significantly reduced body weight as well as lowering blood sugar levels and cholesterol.

“This rigorous assessment of the best available evidence to date indicates with reasonable certainty that adhering to a vegan diet for at least 12 weeks may result in clinically meaningful weight loss and improve blood sugar levels, and therefore can be used in the management of overweight and type 2 diabetes, ” said Anne-Ditte Termannsen, of the Steno Diabetes Centre in Copenhagen, who led the research.

Termannsen AD, Clemmensen KKB, Thomsen JM et al. 2022. Effects of vegan diets on cardiometabolic health: A systematic review and meta-analysis of randomized controlled trials. Obesity Reviews. Epub ahead of print.

Focus on cancer

Dairy increases risk for prostate cancer

Research shows men who consume dairy, especially milk, have a higher risk of prostate cancer than those consuming little or no milk. This study found that men consuming 430 grams of cows ’ milk (1¾ cups) a day had a 27 per cent higher risk compared to those consuming 20 grams (half a cup) a week and a 63 per cent higher risk than those consuming none at all.

The biggest increases in risk were seen at relatively low intakes of dairy and there was little difference between full-fat and low-fat products. Non-dairy sources of calcium such as plant milks did not increase the risk and the authors say that the difference could be due to sex hormones in dairy milk. Up to three-quarters of lactating cows are pregnant, when their hormone levels are high, and prostate cancer is a hormone-responsive cancer. It may also be due to the growth hormone IGF-1, which promotes certain cancers, including prostate.

Professor Gary Fraser, the study ’ s principal investigator, said: “The parallels between our breast cancer in women paper a year ago and this paper relating to men, are striking. It seems possible that the same biological mechanisms are at work. ” He added: “If you think you ’ re at higher-than-average risk, consider the alternatives of soya, oat, cashew and other non-dairy milks.

Orlich MJ, Mashchak AD, Jaceldo-Siegl K et al. 2022. Dairy foods, calcium intakes, and risk of incident prostate cancer in Adventist Health Study-2. American Journal of Clinical Nutrition. Epub ahead of print.

Plant-based diets reduce risk of breast cancer

Plant-based diets reduce the risk of breast cancer in postmenopausal women, according to research presented at a meeting of the American Society for Nutrition. Researchers collected data from over 65,000 women and found that those who followed a healthy, plant-based diet of fruit, vegetables, pulses and wholegrains, for the longest period of time, had the least risk of cancer compared to those who ate animal products and less healthy foods.

Shah S, Mahamat-Saleh Y, Ait-Hadad W et al. 2022. Adherence to healthy and unhealthy plantbased diets and risk of breast cancer overall and by hormone receptor and histologic subtypes among postmenopausal women. Abstract presented at: Nutrition 2022, annual meeting of the American Society for Nutrition; June 14-16, 2022.