Category: Longevity & Health

Researchers at the London School of Hygiene and Tropical Medicine have found that commuters who travel to work by walking, cycling or public transport, have a significantly lower body mass index (BMI) and percentage body fat, compared with those who use private transport (predominantly the car, but also taxi, moped and motorbike).

A total of 15 777 people were included in the study. Factors such as age, disability, diet quality, participation in sport, and physical activity in the workplace, were all allowed for in anticipation that they might affect any association between commuting mode and obesity. Men who commuted via public or active transport modes were found to have BMI scores respectively 1.10 and 0.97 lower than those using private transport. For women, the corresponding figures were 0.7 and 0.87.

A key finding was that the effects observed for public transport were very similar in size to those for walking or cycling, probably due to walking between transport hubs and making journey connections. The observed effect size for men of around 1 BMI point suggests that, for the average man in the sample (43 years old, 176 cm tall, weight 86 kg, and BMI 27.8), this would equate to a difference in weight of 3 kg (almost half a stone). For the average woman in the sample (43 years old, 163 cm tall, weight 72.8 kg, BMI 27.4), an effect size of around 0.7 BMI points would correspond to a difference in weight of approximately 2.5 kg (5.5 lb).

(Associations between active commuting, body fat, and body mass index: population based, cross sectional study in the United Kingdom. British Medical Journal, online 19 August 2014.)

An international team of researchers, led by Dr David Llewellyn at the University of Exeter Medical School, has found that vitamin D deficiency is associated with a substantially increased risk of dementia and Alzheimer’s disease in older people. The team followed 1658 individuals in the US, who were initially free from dementia, cardiovascular disease and stroke, for a mean of 5.6 years. Their blood vitamin D levels were monitored and classified as severely deficient, moderately deficient or sufficient.

The researchers found that those participants who were moderately deficient in vitamin D had a 53% increased risk of developing dementia of any kind, and this risk increased to 125% in those who were severely deficient. Similarly, for Alzheimer’s disease, the moderately deficient group were 69% more likely to develop this type of dementia, and this risk increased to 122% for participants who were severely deficient.

Dr Llewellyn commented that the association was twice as strong as anticipated, and that clinical trials are now needed to establish whether eating foods such as oily fish or taking vitamin D supplements can delay or even prevent the onset of Alzheimer’s disease and dementia. The team outlines how their study design makes reverse causation unlikely (dementia itself leading to lower vitamin D levels), and that their findings support the idea that vitamin D may possess a neuroprotective effect.

(Vitamin D and the risk of dementia and Alzheimer disease. Neurology Journal, on-line 6 August 2014. Link Between Dementia and Vitamin D Confirmed

A large study undertaken at Harvard Medical School seems to show that people who include significant quantities of nuts in their diets, can reduce their mortality risk: those who ate nuts seven or more times per week, reduced their risk of dying by around 20%. The researchers followed 76000 women and 42000 men for between 24 and 30 years, during which time the subjects kept records of their consumption of nuts. On analysis, both nuts and peanuts were found to reduce the chance of dying from cardiovascular disease, cancer, diabetes, infectious diseases, lung and kidney diseases.

Parallels have been found in other research from Iowa, the UK and Holland. The researchers speculate that nutrients in nuts, such as unsaturated fatty acids, high-quality protein, fibre, vitamins (folate, niacin, vitamin E), minerals (potassium, calcium, and magnesium), and plant chemicals (carotenoids, flavonoids, and phytosterols), may confer cardioprotective, anti-cancer, anti-inflammatory, and antioxidant properties.

(Association of nut consumption with total and cause-specific mortality. New England Journal of Medicine, 21 November 2013.)

Meanwhile, research at Loma Linda University in California, suggests that walnuts may have the ability to prevent “bad” cholesterol (LDL) from oxidising and damaging our blood vessels. The researchers wanted to build on previous work which has shown associations between high nut consumption and lower rates of cardiovascular disease and obesity. Although this is normally attributed to the presence in nuts of unsaturated fatty acids, they were interested in whether other constituents are preventing oxidative damage to the body. Sixteen healthy volunteers were given a breakfast of either 90g walnuts with water, or a breakfast similar in macronutrients made from olive oil, white bread, dried egg powder and water. Blood analysis would appear to indicate an antioxidant effect aswell as reduced inflammatory responses in individuals when consuming the walnut meal.

(Effect of a walnut meal on postprandial oxidative stress and antioxidants in healthy individuals. Nutrition Journal, Volume 13, 2014.)

A study of professional baseball players has shown that the benefits of building strong bone during youth, can last a lifetime. The research also confirmed that continued physical activity can help in maintaining bone strength as we age.

Researchers at Indiana University recruited more than a hundred baseball players at different stages of their careers. Baseball players have an internal control for such a study: their throwing arms are exposed to repeated loads, while their non-throwing arms are not. They also usually retire from throwing activities once they stop professional play. This allowed assessment of the effects of physical activity long after the players’ left and right arms had settled into becoming subject to similar daily loading. Almost a hundred age-matched controls were studied for comparison.

The researchers focused on the humerus, the bone of the upper arm, and used CT scans and dual-energy X-ray absorptiometry (DXA) to measure bone size and density. They found that the loads on the throwing arms caused the bones there to nearly double in strength, extra bone having formed on the outer surface of the humerus. Compared to humeral bones in non-throwing arms, those in throwing arms had about 50% greater mass, size (total cross-sectional area), and thickness.

After retirement, these bone mass benefits from throwing were gradually lost. Bone loss during aging however, occurred mostly on the inside of bones rather than the outside. Because of this pattern of bone loss, about half the bone size benefits of physical activity during youth and one-third of the bone strength benefits were maintained lifelong. Players who continued throwing as they aged, experienced less bone loss on the inside of the bone and maintained even more of the strength benefits.

The researchers conclude that exercise during youth adds extra layers to the outer surface of a bone to essentially make the bone bigger, and since bone loss during aging predominantly occurs on the inside rather than outside of a bone, the bigger bone generated by physical activity when young is an enduring means of keeping the skeleton stronger.

(US National Institutes of Health, 31 March 2014.)

A study spanning 30 years has found that men with healthy lifestyles enjoy longer, healthier lives and reduced likelihood of cognitive impairment as they age. In the Caerphilly Prospective Study, 2235 men aged 45 to 59, were enrolled in 1979 to take part in a long-term evaluation. Over the following three decades, they were repeatedly questioned and examined, and it has been found that those following at least four out of five healthy behaviours (regular exercise, not smoking, maintaining a healthy weight, healthy eating & moderate drinking), showed:

– a 50% reduction in diabetes and vascular disease;
– a 60% reduction in cognitive impairment and dementia;
– a 60% reduction in all-cause mortality.

Exercise conferred the strongest protective effect against cognitive impairment and dementia. Only 5% of men though, adhered to at least four healthy behaviours, with those adhering to all five, amounting to just 1%.

(Healthy lifestyles reduce the incidence of chronic disease and dementia: evidence from Caerphilly cohort study. PLoS One, December 2013.)