How the human body ages, and why we should keep exercising and load up on antioxidants
Scientists show it is more than mere common sense that, as we get older, we lose muscle strength and kidney function. Also in the news: why it’s better to be pear-shaped than apple-shaped
The scientific keys to successful ageing
Researchers at Japan’s Okinawa Institute of Science and Technology have recently discovered metabolites – substances created during metabolism – that are specifically related to ageing, shedding light on how the human body ages. Working with collaborators at Kyoto University, the scientists obtained blood samples from 30 healthy people: 15 young adults (average age 29) and 15 older adults (average age 81). Fourteen age-related metabolites were found, half of which had decreased in elderly people. “The decrease was found in antioxidants and compounds related to muscle strength. Therefore, elderly people had fewer antioxidants and less muscle strength,” says lead researcher professor Mitsuhiro Yanagida. The other half of the compounds that had increased were metabolites related to declining kidney and liver function. Says Yanagida: “Common sense says that as we get older we lose abilities like muscle strength and kidney function, but no one has ever scientifically proved that this is the case before.” The decline in antioxidants and muscle strength suggest that it is important for individuals to consume foods high in antioxidants and to continue exercising, especially after the age of 65. This could help increase the levels of the related metabolites in the body and improve body condition.
Waist circumference is stronger predictor of heart disease than BMI
It’s better to be shaped like a pear – with weight around the hips – than an apple, according to a new study from the Intermountain Medical Centre Heart Institute in Salt Lake City and Johns Hopkins Hospital in Baltimore. Researchers from the two centres in the United States found that abdominal obesity (being apple-shaped) is a strong predictor of serious heart disease in patients who have type 1 or type 2 diabetes and haven’t displayed any symptoms of heart disease. Apple-shaped bodies are already associated with metabolic syndrome (which includes high blood pressure, high sugar levels and high cholesterol), as well as coronary artery disease and heart failure, but this new study found that waist circumference is also a strong predictor of left ventricular dysfunction in patients. The researchers studied 200 diabetic men and women who had not yet exhibited any coronary disease. The researchers found that even independently of total body weight and body mass index or BMI, abdominal obesity was strongly associated with regional left ventricular dysfunction, which is a common cause of heart disease, including congestive heart failure. The left ventricle is the chamber of the heart that pumps oxygen-rich blood to the brain and the body. When there’s a dysfunction in the left ventricle, blood backs up into the lungs and lower extremities, which often leads to heart failure and increases the risk of sudden cardiac arrest.
Another reason to break the habit: smoking alters bacterial balance in the mouth
Smoking drastically alters the oral microbiome, the mix of roughly 600 bacterial species that live in people’s mouths, finds a new study led by researchers at New York University’s Langone Medical Centre. Recent work in the field links imbalances in microbial populations in the gut to such immune disorders as Crohn’s disease, as well as to some gastrointestinal cancers, but the biological implications of changes in the oral microbiome are not yet known. “Further experiments will be needed, however, to prove that these changes weaken the body’s defences against cancer-causing chemicals in tobacco smoke, or trigger other diseases in the mouth, lungs, or gut,” says study senior investigator and epidemiologist Jiyoung Ahn. The researchers analysed mouthwash samples from 1,204 American men and women aged at least 50 years. Participants included 112 smokers, 571 former smokers and 521 people who never smoked. More than 150 bacterial species showed significantly increased growth in the mouths of smokers, while another 70 showed sharp decreases in growth. For instance, smokers had 10 per cent more species of Streptococcus (known to promote tooth decay) than non-smokers. It was also found that the oral microbiome of smokers bounces back after they quit smoking, with all former smokers (who had not smoked for at least 10 years) showing the same microbial balance as non-smokers.
Gluten-free noodle revolution: the quest for chewier, non-allergenic buckwheat
Your favourite Japanese soba and other gluten-free, buckwheat-based foods could soon be tastier, chewier and free from allergens. Kyoto University scientists have sequenced the full buckwheat genome for the first time, identifying genes which could be modified for improved cultivation capability and taste. Researcher Yasuo Yasui explains that buckwheat has major faults as a crop despite a long history of cultivation; buckwheat plants prevent themselves from self-fertilisating, and the grain contains allergens that elicit strong reactions in some people. In the study, Yasui and colleagues found genes related to “mochi-ness”, which refer to the soft, chewy texture of foods such as marshmallows or fresh bagels. “I think we can hope to see foods – including soba noodles and doughy European foods – with radical new sensations appearing on the market in the near future,” Yasui says. “Buckwheat flour can replace wheat flour in a gluten-free diet. One of our next goals is to make buckwheat less allergenic so that buckwheat-based foods become an option for more people.”