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. 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

Antioxidants v stroke.

The Italian segment of EPIC (European Prospective Investigation into Cancer and Nutrition) has reported on how consumption of antioxidants relates to stroke risk.

Dr Nicoletta Pellegrini of the University of Parma analysed data on roughly 42,000 men and women who were free from stroke and heart attacks at the start of the study, and who were followed for an average of 8 years.

Those with a diet high in antioxidants had a 60% lower chance of suffering an ischemic stroke (blocked blood vessel). Most of this effect may be due to high vitamin C intake.

The researchers speculated that the protective mechanism might be a combination of anti-inflammatory action, plus generation of nitric oxide to cause dilation of blood vessels and so lower blood pressure.

However, highest intake of vitamin E appeared to be linked to a large increase in risk for hemorrhagic stroke (bleeding), but due to the small number of such events, the team suggested further research would be required to investigate this.

More than half the antioxidants consumed came from coffee, red wine and fruit, with other sources including chocolate, vegetables, whole grain cereals and nuts.

While the team checked results after adjusting for a number of risk factors, one notable item they did not account for was sodium (salt) consumption.

January 3, 2011 Posted by | Alcohol, Chocolate, Coffee, Diet, Fruit, Health, High blood pressure, Stroke, Success, Vegetables, Vitamin C - ascorbic acid, Vitamin E | Leave a comment

Orange juice v blood pressure.

Dr Christine Morand and colleagues in France have been investing the impact of orange juice on blood pressure, and whether this is due to an ingredient called hesperidin, a polyphenol found in citrus fruits.

Volunteers were healthy but overweight males, aged 51 to 63. They were split into 3 groups, one drinking orange juice, a second drinking a control drink but taking hesperidin, and a third drinking the control drink with a placebo capsule.

To make sure the effects found were genuine, the volunteers rotated between these groups at given intervals.

Diastolic blood pressure (the lower blood pressure when the heart is at rest) was found to be reduced by a statistically significant margin after 4 weeks of drinking orange juice or the control drink plus hesperidin.

Various biomarkers showed that although hesperidin was producing the bulk of a number of benefits, orange juice was even better, suggesting at least one further active ingredient.

The amount consumed in the study was quite high, at half a litre per day, an amount that contains nearly 200 calories.

Oranges v supplements recently reported a US study to identify other active ingredients in oranges.

January 1, 2011 Posted by | Diet, Fruit, Health, High blood pressure, Success | 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

Vitamin B1 v heart attacks.

A particular form of vitamin B1 called benfotiamine has been found to protect against heart attacks and aid recovery from heart attacks.

Vitamin B1 is also called thiamine and thiamin. It is water soluble. Benfotiamine is an analog of B1 (has the same action) but it is fat-soluble.

A team reported a study of heart attacks in mice with and without diabetes, in the Journal of Molecular and Cellular Cardiology. The aim was to find out whether a supplement of benfotiamine improved the chances of surviving a heart attack in diabetic mice. It turned out that the supplement improved the chance of survival of both diabetic and non-diabetic mice.

The mice study was backed up by a lab dish study of human heart cells. This showed that benfotiamine cut the risk of cell death when the cells were starved of oxygen, as happens in a heart attack.

There were other benefits, such as reduced diastolic blood pressure in diabetics before a heart attack, reduced blood pressure in both groups after a heart attack and growth of new blood vessels in the damaged area of the heart.

The levels at which the mice were supplemented, 70mg/kilo, is far in excess of the human bodies normal storage capacity for water soluble B1 – about 30mg – which may be why the researchers chose the fat-soluble version.

Benfotiamine is available as a supplement for humans, while good sources of vitamin B1 are Quorn (30mg/100g), pork, milk, cheese, eggs, peas, beans, fish, wholegrain pasta and wholegrain bread.

Deficiency is rare in the developed world – it leads to beriberi – but studies have found that benfotiamine helps prevent other complications of diabetes.

December 7, 2010 Posted by | CVD - cardiovascular disease, Diabetes, Fish, Health, High blood pressure, Success, Vitamin B1 - thiamine, Whole grain | Leave a comment

Preventing Alzheimer’s?

Earlier in 2010 TeamMcCallum published research showing that beetroot juice lowered high blood pressure. The mechanism was that beetroot is rich in nitrate, bacteria on the tongue convert this to nitrite, which in turn gets converted to nitric oxide. The nitric oxide dilates blood vessels and so lowers blood pressure.

Now Dr Zvonimir S Katusic and team from the Mayo Clinic in Rochester, Minnesota, have researched the apparent risk link between cardiovascular disease (CVD) and Alzheimer’s. The study involved looking at the function of the lining of blood vessels (endothelium) in the brain.

First, the team inhibited the generation of nitric oxide by the vessels. This triggered a series of events that led to increased production of the amyloid precursor protein (APP), and an enzyme that normally cuts APP up so it can be disposed of. This increase in production/disposal led to an increase in the production of beta-amyloid plaque, one of the two major things seen in Alzheimer’s.

They checked the result in mice bred to be deficient in production of nitric oxide. These mice are insulin-resistant and have high blood pressure. The results were the same – more APP, more enzyme to chop it up, and more beta-amyloid plaque production.

According to one of the team “On the cardiovascular side we’ve known for some time that preservation of healthy endothelium is critical to prevent major cardiovascular events. Now it seems this may have important implications for cognitive impairment.”

Risk factors for CVD (high cholesterol, diabetes, high blood pressure, smoking, sedentary lifestyle and aging) have all been associated with inability of the endothelium to produce enough nitric oxide. Now they are linked by this research to Alzheimer’s.

This explains the protective effect of, say, exercise. And beetroot juice too!

December 4, 2010 Posted by | Aging, Alzheimer's, Cholesterol, Cognitive decline, CVD - cardiovascular disease, Exercise, High blood pressure, Obesity, Smoking, Success | 1 Comment

Calcium and vitamin D by IOM.

The Institute of Medicine (IOM) was asked by US and Canadian health authorities to conduct an independent, evidence based review of the dietary requirements for calcium and vitamin D.

Overall, the committee concludes that the majority of Americans and Canadians are receiving adequate amounts of both calcium and vitamin D. Further, there is emerging evidence that too much of these nutrients may be harmful.”

Prof A Catherine Ross chaired the committee conducting this update, the first since 1997. The team reviewed over 1,000 studies on vitamin D and calcium and took further evidence from experts.

The review covered all health outcomes,  including cancer, cardiovascular disease, high blood pressure, diabetes, metabolic syndrome, falls, immune response, neuropsychological functioning, physical performance, preeclampsia, and reproductive outcomes. It found that only in relation to bone health are the results unequivocal, and based its recommendations on this.

The committee noted that studies appearing in the media re population levels of deficiency are using arbitrary levels that have not been established by a central authority, and so have little validity.

Based on available data, the committee found almost all individuals get sufficient vitamin D when their blood levels are at or above 20 nanograms per milliliter as it is measured in the US, or 50 nanomoles per liter as measured in Canada.

Also, the committee considered that few people are getting their vitamin D from sunlight, and based their recommendations on this.

A full breakdown of the recommendations by age range and gender is at the IOM short report on calcium and vitamin D. Please note a number of special situations are omitted from this but are covered by the full 678 page report, so check with your physician.

Some subgroups—particularly those who are older and living in institutions or who have dark skin pigmentation—may be at increased risk for getting too little vitamin D.

National surveys in both the United States and Canada indicate that most people receive enough calcium, with the exception of girls ages 9-18, who often do not take in enough calcium. In contrast, postmenopausal women taking supplements may be getting too much calcium.

Too much calcium is linked with kidney stones, while too much vitamin D is linked to kidney and other tissue damage. The short report therefore gives 3 values for each group – the estimated average amount (enough for the average person), the recommended dietary allowance (the level at which nearly everyone gets enough) and the upper level intake (the level at which more will cause harm rather than good).

In conclusion, “the committee emphasizes that, with a few exceptions, all North Americans are receiving enough calcium and vitamin D. Higher levels have not been shown to confer greater benefits, and in fact, they have been linked to other health problems, challenging the concept that “more is better.””

November 30, 2010 Posted by | Aging, Calcium, Canada, Cancer, Child Health, Cognitive decline, CVD - cardiovascular disease, Diabetes, Gender, High blood pressure, IOM - Institute of Medcine, Metabolic syndrome, Success, United States, Vitamin D | 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

Jet-lagged hamsters?

What can we learn from jet-lagged hamsters? Quite a lot, according to a study by a team from the University of California Berkeley.

Syrian hamsters are used regularly in the study of circadian rhythms because they follow these very precisely.

The team jet-lagged the hamsters twice a week for four weeks by shifting their light-dark cycle by six hours. This is about the same as flying the North Atlantic, or what you might get on rotating shift patterns.

During this period, the team was not surprised to find that the hamsters had more difficulty when set learning tasks. However, the effects were found to persist for a month after the time switching was stopped. This suggests the human equivalent would last much longer.

The researchers dug deeper to identify the mechanism for this. Using a number of procedures they were able to rule out secondary effects produced by stress from elevated cortisol.

This left only one explanation. A part of the brain called the hippocampus is essential for memory and learning, and it works by neurogenesis – creating new neurons to ‘store’ the new memories. The time shift was cutting neurogenesis, so the hippocampus was not producing enough new neurons for efficient memory formation. This same problem occurs in humans suffering from cognitive decline.

Rotating shift work has been associated with learning and memory problems, decreased reaction times, higher incidences of diabetes, heart disease, hypertension and cancer, and reduced fertility, and has been listed by the World Health Organization as a carcinogen.

November 27, 2010 Posted by | Brain, Cancer, Cognitive decline, CVD - cardiovascular disease, Health, High blood pressure, Learning, Memory, Success | Leave a comment