Team McCallum

R&D for Lifetime of Life

Walking v diabetes+.

Dr Terry Dwyer and colleagues have found that walking cuts the risk of diabetes in a study of 600 adults in Tasmania. While the team focussed on diabetes, the results suggest a protective effect against metabolic syndrome and cardiovascular disease.

Roughly 600 adults aged around 50 in 2000 were tracked for 5 years.  At the start, most were overweight or obese and as a whole, the group gained weight over the period.

The volunteers were fitted with pedometers for 2 days in 2000. One finding was that those with higher daily step counts at this start time ended with a better body mass index (BMI), better waist to hip ratio and better insulin sensitivity, compared to those less active.

After 5 years, the group wore pedometers for another 2 days. As a whole, the group gained weight and became less active.  However, one third stayed active or increased their steps in the period, and again these were the ones with better measures on BMI, waist-hip ratio and insulin sensitivity.

The following figures are for those walking 10,000 steps, which is about 5 miles or 8km.

For a person of average height, weight dropped was just under 3kg, or about 6lbs. This corresponds to a BMI reduction of 0.83kg/metre squared. Insulin sensitivity increased by about 12%, with men doing slightly better than women.

These results are all ‘dose-dependent’. In other words, walking less still resulted in some improvements.

When the researchers factored in BMI, the differences between those active and those not disappeared, so the team attributed the improvement to a cut in body fat.

The researchers were looking at diabetes, and the improvement in insulin sensitivity would result in a considerably reduced risk of the disease.

The figures also strongly suggest there would be an improvement in other diseases linked to BMI and larger waists, including high blood pressure, metabolic syndrome, cardiovascular disease and more.

The impact on the waist is interesting, since fat stored around the waist is linked to adiposopathy (sick fat), and this study suggests that walking is a way to burn ‘sick’ fat preferentially to ‘healthy’ fat, reducing the waist to hip ratio.

January 17, 2011 Posted by | Accelerometer, Activity, Adiposopathy - sick fat, Aging, BMI - body mass index, CVD - cardiovascular disease, Diabetes, Exercise, High blood pressure, Metabolic syndrome, Success, Waist circumference, Walking, Weight management | Leave a comment

Udiet: the battlefield.

2010 was stuffed with debate over the reasons why people in developed countries are getting heavier.

 The most simplistic explanations focussed on overeating, or inactivity, or both. HFCS (high fructose corn syrup) also came in for a beating. The problem with this is that Europe imports very little HFCS, but countries in Europe are reporting more and more problems associated with obesity.

 www.obesitymyths.com comes up with a much larger range of interesting possibilities. But in 2005, the New York Times linked this site to sponsorship from fast food producers such as Coca-Cola and McDonald’s, in this article.

Two reputable groups of scientists published work where they found that the mantra of ‘eat less and exercise more’ doesn’t cover all of the potential reasons.

 A government group in the UK called Foresight was asked to predict what will happen there over time, based on best evidence, and building in realistic assumptions. In order to do so, they had to scour published research to identify the drivers of obesity and build a very detailed model of which drivers are most important. Written in simple English, this is probably the best explanation there is of the obesity epidemic.

The full report is available as a free PDF download here. However, at over 160 pages, it won’t be everyone’s cup of tea.

The second group of scientists published a summary of obesity drivers in November 2009. Again, this is available free using this link.

Their findings outline the battlefield for the Udiet.

1. Overeating, particularly re heavily marketed energy dense foods.

2. Underactivity, again with an organisation driver behind it.

3. Infection caused by bacteria and viruses.

4. Epigenetics, whereby prenatal and early postnatal exposure to the environment alters how genes are expressed without changing the genes. For example, babies born very underweight at birth who are incubated and fed rich diets to catch up weight have a higher risk of obesity and associated issues later in life.

5. Increasing maternal age. Animal studies have shown that babies born to older mothers are fatter than those born to younger mothers.

6. BMI breeding effect. Studies have found that those with a body mass index somewhat above average are producing slightly more children, on average, than the rest of the population, causing the population BMI to increase over time.

7. Assortitative mating is taking place. This hypothesis is that those with higher BMI prefer partners of similar kind, and due to the genetic effect, this leads to even heavier children. A wide range of population studies support this idea.

8. Sleep debt is happening, and leads to increased eating, increased fat deposition and lowered activity. Research shows metabolic changes occur to support this, and also leads to higher risk of diabetes and heart disease. For example, one study shows that getting one and a half hours less sleep than ideal over a two week period results in a diabetic-like profile for glucose and insulin.

9. Endocrine disruptors interfere with estrogen and androgen signalling, and have been building up in the human environment for some time.  These have been found to be involved in obesity in animals and in humans.

10. Commonly used medicines are known to contribute to weight gain. These include medicines for diabetes, high blood pressure, steroids, contraceptives, and anti-histamines.

11. Artificial ambient temperature. The hotter your environment, the less energy you burn keeping warm. The UK home went from 13 centigrade in 1970 to 18 centigrade by 2000. US homes went from 18 centigrade in 1923 to nearly 25 centigrade in 1986.

12. Mothers input. The state of the mother’s glucose and insulin handling systems directly affect the number of fat cells and the fat cell content of the baby.

13. Reduction in smoking rate. The scientists considered this so well documented they excluded it from their list.

14. Altered US demographics. A 2006 article along the same lines had found that alterations in the US population were increasing the races which tend toward higher BMI, therefore  increasing the average BMI of the nation.

The aim of the scientists’ report was not to remove the first two reasons from focus, but to show that the battlefield is considerably more complex than simply food and exercise.

These 14 points are not comprehensive. For example, other researchers have found that altering the circadian rhythm, by staying up late in artificial light and not synchronising your body clock to early morning light, is also a risk factor for weight gain. Also, breastfeeding v formula milk wasn’t mentioned, although formula milk is associated with higher risk of obesity.

January 9, 2011 Posted by | Activity, BMI - body mass index, Breastfeeding, Child Health, CVD - cardiovascular disease, Diabetes, Environment, Epigenetics, Exercise, HFCS - high-fructose corn syrup, High blood pressure, Obesity, Pregnancy, Pregnancy, Success, Thermogenesis, UK, United States, Weight management | Leave a comment

Long life and health.

In Feb 2010, our top story was that researchers in Australia had found that the body mass index (BMI) guidelines used for the general public are not the best ones for seniors. Later in the year, this article was cited by another one entitled “Survival of the Fattest”.

The BMI ranges used by the Australian team were 18.5 to 25 as normal, 25 to 30 as overweight, over 30 as obese, and under 18.5 as underweight.

The research published in the Journal of the American Geriatrics Society compared all-cause mortality, and cause specific mortality (cardiovascular disease, cancer, chronic respiratory disease) across the groups. Nearly 5,000 men and 5,000 women aged 70 to 75 at the start of the study were followed for a period of 10 years.

Compared to the normal weight group, those overweight had an 18% less risk of dying during the study. Even the obese group came in at the same risk as the normal weight people.

Another key finding was that being physically active made a large difference. Compared to an active lifestyle, men who were sedentary increased their risk of death by 28%, while inactive women more than doubled their risk.

The short meassage was fatten up a bit, but make sure you stay active. (Staying active is a theme we’ll return to in the rest of the year’s highlights).

This Australian research has already been cited by 5 other articles published in 2010.

In Sep 2010, 2 researchers wrote an article in the Journals of Gerontology Series A entitled ” Adaptive Senectitude: The Prolongevity Effects of Aging.”

This raised the question that some of the effects we normally think of as declines in old age, (including high blood pressure, metabolic syndrome, and obesity) may in fact be protective, while anti-oxidants and hormone supplements may be damaging. Or in other words, we don’t yet understand optimal aging.

Today, 29 Dec 2010, a group of scientists which appears to be related to those carrying out the February study has published in the Australasian Journal on Ageing, uder the title ” Are the national guidelines for health behaviour appropriate for older Australians? Evidence from the Men, Women and Ageing project”.

Here is their recipe for long life and health.

“Current BMI guidelines may be too narrow because BMI in the overweight range appears to be protective for both older men and women. Across all levels of BMI, even low levels of physical activity decrease mortality risk compared with being sedentary. Our findings suggest that consideration should be given to having different alcohol guidelines for older men and women and should include recommendations for alcohol-free days. The benefit of quitting smoking at any age is apparent for both women and men.”

December 29, 2010 Posted by | Activity, Aging, Alcohol, BMI - body mass index, Health, High blood pressure, Metabolic syndrome, Obesity, Smoking, Success, Weight management | Leave a comment

Fat kids v teen heart risk.

A study in the UK has looked at over 5,200 children, to see whether being overweight at age 9-12 is associated with cardiovascular risk factors at age 15-16. It also investigated whether body mass index (BMI) is useful, or whether other measures are better.

Dr Debbie A Lawler and colleagues took measurements of BMI, waist circumference and fat/lean mass by dual energy x-rays at start point and end point. For 75% of the children, the start was before age 10.

At the end, at age 15-16, a wide range of risk markers associated with cardiovascular disease (CVD) were measured.

Different detailed results were found for boys and for girls. However, in general, those overweight at the start point were at higher risk  of factors linked to CVD. (The ‘overweight’ definition used was that of the International Obesity Task Force.)

The following risk factors were all predicted – high systolic blood pressure, high ‘bad’ LDL cholesterol, low ‘good’ HDL cholesterol, high triglycerides, high insulin in blood. BMI was linked to high fasting glucose levels in boys only, and risk for some of the others was worse in boys than girls.

Diastolic blood pressure at the end was not predicted by BMI at the start measurement.

Girls who went from overweight at the first point into the normal range by the end were found to have no more risk than those girls in the normal range at both times. However, boys who improved their weight status also improved their risk profile, but it remained poorer than those in the normal range at both times.

Finally, the team found that although BMI is much criticised, it was as good a predictor as the other two methods, even the very precise x-ray method. So BMI was validated as a simple and easy way to predict a child’s future health profile.

November 28, 2010 Posted by | BMI - body mass index, Child Health, Cholesterol, CVD - cardiovascular disease, Gender, Health, High blood pressure, Metabolic syndrome, Obesity, Success, Waist circumference, Weight management | Leave a comment

Vitamin D v genes?

A study in white males living in the US has concluded that vitamin D levels are 70% determined by genetics in winter but in summer this is replaced by environmental factors, such as sun exposure.

The research, published in the American Journal of Clinical Nutrition, was based on twins from the Vietnam Era Twins (VET) registry, one of the largest in the US, so the men had an average age of 55 when studied.

The men were followed over 12 months to find out the level of vitamin D in their blood in each month, to allow comparison to be drawn between the 6 months aggregated into ‘summer’ and the other 6 called ‘winter’.

Then a standard routine for determining the genetic component was used. Identical twins are assumed to be 100% identical genetically, while for non-identical twins this is 50%. Twins living together are assumed to have a 100% shared common environment, while  those living apart have a unique environment. Blend these into the results, and genetic and environmental components can be teased out.

The researchers from Brazil and the US found that, in general, people with lower blood levels of vitamin D had a larger body mass index, a larger waist-hip ratio (a marker for cardiovascular disease), a higher Framingham risk score (a marker for coronary artery disease) and a higher percentage were diabetic.

And when doing the twins analysis, they found that genetics dominate in winter (70%), but in summer this impact disappeared, and the determinants were environmental, with 53% due to shared environments and 47% due to unique environments.

The team noted other research has found that genetic factors appear to have much less influence in women.

They also raised an interesting point that they did not resolve. Other studies have found that in white people (but not in non-whites), vitamin D levels decrease the further north you live, due to less UVB in sunlight. However, the current team could not find this effect in their subjects, despite the fact that they ranged from 21 degrees N to 49 degrees N.

While the town of Uppsala in Sweden is 60 degrees N. The current study noted previous research in white twins, both male and female,  from Uppsala, which found things worked the opposite way around. That team reported that genetic factors were important in summer, at 48%, but in winter were replaced by a mix of shared and unique environments. Quite why Sweden appears to work in the opposite direction to the US was not explained.

November 19, 2010 Posted by | BMI - body mass index, CVD - cardiovascular disease, Diabetes, Genetics, Health, Vitamin D, Waist circumference | 1 Comment

Exercise beats colds.

Prof David C Nieman has found that the way to avoid getting colds in the first place, and cut the severity of those you do catch, is moderate exercise. Thinking of yourself as fit also had the same effect, although this seems to be mainly an overlap with exercising regularly.

Nieman’s team followed 1,000 US adults, aged 18-85 for 12 weeks, half during autumn and half during winter.

People rated how fit they thought they were on a 10 point scale. They logged when they did moderate exercise, defined as 20 minutes or more at one time.  Frequency and severity of colds were also logged using a validated method.

The team then stripped out a number of factors to get at the fitness impact.  When they did this and compared those in the top third against those in the bottom third,  regular moderate exercise ( 5 days per week) cut the number of days with a cold by nearly half, while the severity was cut by around a third.  Perceived fitness overlapped with actual exercise and produced much the same result.

The authors suggested that regular moderate exercise might be periodically boosting the immune system. Since the boost is short-lived (a few hours), the ‘regular’ part is explained.

‘Moderate’, just enough to break into a sweat, is also important. Moderate exercise does not elevate stress hormones (which can suppress the immune system rather than boosting it), while hard exercise does boost stress levels.

These effects all dose-dependent. The more active people were, even at levels lower than above, the fewer days spent with a cold.

Plugging the other factors back in, the following all cut the risk of getting a cold – older age, medium or high fitness, lower education, being male, being married, having a higher body mass index and eating fruit. The biggest modifiable factor was still exercise.

November 2, 2010 Posted by | Activity, Aging, BMI - body mass index, Cold - common cold, David C Nieman, Diet, Exercise, Health, Success | Leave a comment

Pine bark fails heart test.

Pine bark extract failed to produce any improvement in cardiac risk profile in a 12 week randomised trial,  compared to a placebo.

Dr Randall Stafford randomly allocated 121 volunteers with high blood pressure to 200 mg/day of pine bark extract or a placebo for 12 weeks.

According to food records at start and end, the pine bark group increased potassium intake by 75 mg/day while the placebo group fell by nearly 300 mg/day.

An increase in potassium is normally linked to a decrease in blood pressure. However, the pine bark group decreased by 1 mm while the placebo group decreased by nearly double this.

The body mass index of the pine bark group increased slightly while the control group BMI decreased slightly, leading to a small but significant difference between the two.

Other markers for cardiovascular risk were the same across both groups.

The researchers noted that “Although a different dosage or formulation might produce different results, our findings argue against recommending this pine bark extract to improve cardiovascular disease risk factors.” The pine bark extract tested was from Toyo Shinyaku of Japan.

September 28, 2010 Posted by | BMI - body mass index, CVD - cardiovascular disease, Health, High blood pressure, Natural healing, Randall Stafford, Success | Leave a comment

Neighbourhood choice test.

Pretend that you are going to move soon. Rate the desirability of the following two characteristics for your new neighbourhood, from not important at all to very important –
– ease of walkability
– close to outdoor recreation facilities.

Dr Tanya R Berry examined the relationship between a number of reasons for choosing a neighbourhood and weight change in nearly 1,800 Canadians over a period of 6 years, and found some odd results.

Weight and body mass index (BMI) tend to increase with age, so the question was who would gain the most or gain the least.

A number of desires relating to neighbourhood choice made no difference to weight gain, but walkability and close to outdoor recreation did.

Those who rated walkability highly gained less than those who did not care about it.

But those who rated nearness to outdoor recreation highly gained more than those who did not care about this, a finding that the researchers could not explain in this study.

September 25, 2010 Posted by | Activity, BMI - body mass index, Success, Tanya R Berry, Walking, Weight management | Leave a comment

Genes – weight – exercise.

Dr Ruth Loos has looked at the effect of genetics and exercise on weight in a large study of people in Norfolk.

20,400 were followed for 3 and a half years. Various measurements including body mass index (BMI) and physical activity levels were taken at the start.

Each person had their genetics sequenced for 12 known ‘fat’ genes, with each of these scoring no copies, 1 copy or 2 copies, giving a 0-24 total.

Nearly 12,000 of these people also had their BMI measured at the end, so changes could be tracked over time.

For a person of 1m 70cm (5ft 7″), each ‘fat’ copy they had added 454g (1lb). For the inactive, this went up to 592g, while for the active this was 379g, a saving of about 36%.

Over the duration of the study, the inactive group gained weight, while the active group lost as much weight as the inactive group gained.

In the study, inactive was a sedentary job combined with no recreational activity. Active was anything equivalent to at least an hour a day of recreational activity or a heavy manual job. Intermediate levels produced intermediate results.

Prof Theodore Garland Jr finds out that activity/exercise has a strong genetic basis!

September 1, 2010 Posted by | Activity, BMI - body mass index, FTO rs9939609, Genetics, Obesity, Ruth Loos, Success, Theodore Garland Jr, Weight management | 1 Comment

Supplements v weight gain.

Dr Lan-Juan Zhao studied the effect of calcium supplements and vitamin D supplements v weight gain in post-menopausal white women over a period of 4 years, with 870 completing the study.

The team concluded “Study results show beneficial effects of high calcium intake on obesity in a population-based study of postmenopausal women who have a relatively high baseline calcium intake. However, vitamin D supplementation may have no additional effect on body composition.”

One group of women took calcium plus vitamin D, another calcium plus placebo, while the controls took two placebos.

Overall, there was no clinically significant difference in body mass index changes for the 3 groups (although calcium plus vitamin D was slightly better than calcium only which edged ahead of none).

What was significant was that both calcium groups retained more lean tissue and lost more fat in the body trunk than the control group.

The team thought the fact that most of their drop-outs left in years 1 and 2 was not significant for the results. However, the calcium-only group shows a quick spike in weight gain in year 1, stable in year 2, and returning to base weight only during years 3 and 4.

In comparison, the calcium plus vitamin D group did not spike and showed a (very modest) reduction in BMI by the end.

The amounts taken were 1.4 grams/day of calcium and 1,100 IU of vitamin D3.

August 17, 2010 Posted by | Aging, BMI - body mass index, Bodyfat%, Calcium, Lan-Juan Zhao, Minerals, Obesity, Success, Vitamin D, Weight management | Leave a comment