Restricting the amount of calories we consume, while avoiding malnutrition, may extend lives and reduce the risk of chronic disease, suggest results from a monkey study.

Findings published in Science indicate that 80 per cent of rhesus monkeys who consumed a calorie restricted diet without being malnourished were still alive after 20 years, compared to only 50 per cent of control animals who ate freely.

“We have been able to show that calorie restriction can slow the aging process in a primate species,” said study leader Professor Richard Weindruch from the University of Wisconsin-Madison. “We observed that caloric restriction reduced the risk of developing an age-related disease by a factor of three and increased survival.”

Not surprisingly, longevity and enhanced quality of life is the ultimate aim of most research into diet and nutrition, but very few studies actually achieve such a link. The trick now will be to see if it can be carried over to humans - something the researchers say is highly unlikely due to the extremely restrictive nature of such a diet.

“Our data indicate that adult-onset moderate caloric restriction delays the onset of age-associated pathologies and promotes survival in a primate species,” wrote the researchers.

“Given the obvious parallels between rhesus monkeys and humans, the beneficial effects of caloric restriction may also occur in humans. This prediction is supported by studies of people on long-term calorie restriction, who show fewer signs of cardiovascular aging,” they added.

“The effect of controlled long-term caloric restriction on maximal life span in humans may never be known, but our extended study will eventually provide such data on rhesus monkeys.”

Study details

The Wisconsin-based researchers started their study in 1989 with 30 rhesus macaques (Macaca mulatta), and subsequently expanded this to 76. The animals were divided into two groups; one was allowed to eat freely (control group), while the other group had their energy intake restricted by 30 per cent.

According to Weindruch and his co-workers, macaques typically live for about 27 years in captivity. All the monkeys were aged between 7 and 14 when introduced into the study, they added.

In addition to increased lifespan in the calorie restriction group, a halving of the incidence of cancer and cardiovascular disease was observed in this group, compared to the control animals.

Furthermore, while free eating resulted in diabetes or impaired glucose regulation no animal on the restricted diet developed these conditions. “So far, we’ve seen the complete prevention of diabetes,” said Weindruch.

Brain boosting

Brain health was also better in the animals with restricted calorie diets, said the researchers, particularly the parts of the brain responsible for motor control and executive functions such as working memory and problem solving.

“It seems to preserve the volume of the brain in some regions. It’s not a global effect, but the findings are helping us understand if this dietary treatment is having any effect on the loss of neurons,” said co-researcher Sterling Johnson.

“The atrophy or loss of brain mass known to occur with aging is significantly attenuated in several regions of the brain. That’s a completely new observation,” added Weindruch.

Adding soy sauce to certain foods may enhance perception of saltiness and enable food manufacturers to cut salt content without affecting taste, according to new research from Japan.

Soy sauce was capable of reducing the salt content of salad dressings, soup, and stir-fried pork by 50, 17, and 29 per cent, respectively, without affecting the overall taste intensity or product pleasantness, according to results published in the Journal of Food Science.

Salt is of course a vital nutrient and is necessary for the body to function, and the World Health Organization recommends that per capita daily salt consumption should not exceed five grams. However, with the average daily salt (NaCl) consumption in the western world estimated to be between 10 and 12 grams, consumers and some governments have imposed pressure on food manufacturers to reduce the salt content in their formulations - 60 to 80 per cent of salt consumption comes from packaged foods rather than salt added at the table.

The new research, led by Stefanie Kremer from Wageningen University’s Centre for Innovative Consumer Studies, suggests “that it is possible to replace NaCl in foods with naturally brewed soy sauce without lowering the overall taste intensity and to reduce the total NaCl content in these foods without decreasing their consumer acceptance”.

The study, which involved scientists from Kikkoman Europe, proposed that soy sauce may work by enhancing the perception of saltiness, the so-called odour-induced saltiness enhancement (OISE).

“[However,] it might be expected that the association between soy sauce odour and saltiness in a population of almost completely nonusers of soy sauce might not be very strong. In that case it will take probably more than 1 or 2 sessions to establish an association between soy sauce odour and saltiness,” wrote Kremer and her co-workers.

Study details

The Wageningen and Kikkoman researchers formulated salad dressing, soup, and stir-fried pork with increasing levels of soy sauce and decreasing levels of salt. Consumers were then recruited to test five samples of each product and rate the pleasantness and other sensory attributes.

“The results showed that it was possible to achieve a NaCl reduction in the tested foods of, respectively, 50 per cent, 17 per cent, and 29 per cent without leading to significant losses in either overall taste intensity or product pleasantness,” wrote the researchers.

“These results suggest that it is possible to replace NaCl in foods with naturally brewed soy sauce without lowering the overall taste intensity and to reduce the total NaCl content in these foods without decreasing their consumer acceptance,” they concluded.

Increased intakes of whole grains, and bran in particular, may reduce the incidence of hypertension in men, according to new findings from Harvard.

Data from over 30,000 men participating in the Health Professionals Follow-Up Study indicated that increased intakes of whole grains are associated with a 19 per cent lower incidence of hypertension.

The researchers, led by Alan Flint from Harvard School of Public Health, report their findings online in the American Journal of Clinical Nutrition.

“These findings have implications for future dietary guidelines and prevention of hypertension,” they wrote.

High blood pressure (hypertension),defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg, is a major risk factor for cardiovascular disease (CVD) - a disease that causes almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.

While the potential heart health benefits of whole grains have been reported before, the Harvard researchers note that no studies have reported if the total grams of whole grains are linked to the risk of hypertension.

The 31,684 male health professionals aged between 40 and 75 without known hypertension, cancer, stroke, or heart disease were followed for 18 years. During this time, 9,227 cases of incident hypertension were documented.

Comparing the highest intakes of whole grains to the lowest intakes, the researchers calculated that whole grains were associated with a 19 per cent reduction in the incidence of hypertension.

When they subsequently looked at total bran, a 15 per cent reduction in the incidence of hypertension was observed for men with the highest intakes, compared to the lowest.

“In summary, we found an independent inverse association between intake of whole grains and incident hypertension in men,” wrote the researchers. “Bran may play an important role in this association,” they concluded.