Team McCallum

R&D for Lifetime of Life

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

What did grandad eat?

First, there was genetics, which was going to tell us the whole story simply by sequencing our genes. However, when our genes got sequenced, the picture only got a little clearer.

Then there was epigenetics (epi means above, so epigenetics is above genetics). With epigenetics, your gene sequence does not change, but genes can be switch on or off (pretty much like lightbulbs) by events that happen. Things are getting more complex if you have to account for both the genes and the environment, and the picture is harder to read.

Now comes inherited epigenetics. This means information about the parents’ environment that is passed to offspring, even if the parent never sees the offspring alive (which cuts out passing this by the more simple route of learning). The genes aren’t altered in the child, but expression (whether on or off) is controlled by the environment of the child’s parent.

Various conditions in the mother’s environment appear to get passed on epigenetically, but in this type of study it is hard to rule out mechanisms such as shared environment while in the womb.

So scientists trying to unravel this puzzle are looking at situations where the parent involved is the father, and does nothing more than supply the sperm (with no other influence in the life of the mother or child).

Dr Oliver J Rando and team have been trying to make headway in this using mice. The father was fed a low-protein high-sugar diet, allowed to mate with a female on a standard diet, but with no other contact. Compared to controls (father on standard diet, mother on standard diet) it was found that the offspring had 1600 genes which expressed differently and 500 where the difference was major. This affected blood fat profiles and cholesterol production.

The team couldn’t say whether it was low protein that was important, or high sugar, or some other factor such as low micro-nutrients. And they couldn’t work out how, precisely, this information was passed on, since they couldn’t find a difference in the sperm of the mice.

Unless you are a scientist this is barely interesting. However, the authors point out that two studies have shown inherited epigenetics in the paternal line at work in humans – but it skips a generation.

To at least a certain extent, you are what your grandfather ate.

In 2002, a research team published “Cardiovascular and diabetes mortality determined by nutrition during parents’ and grandparents’ slow growth period”.

In 2006, another team published “Sex-specific male line transgenerational responses in humans”.

These show that a severely restricted diet at key points in your grandfather’s time increase your risk of obesity, diabetes and cardiovascular death, as you are pre-programmed by granddad’s famine-like environment.

December 29, 2010 Posted by | Cholesterol, CVD - cardiovascular disease, Diabetes, Diet, Epigenetics, Genetics, Health, Obesity, Success | Leave a comment

Celiac disease research.

Dr Carlo Catassi of the Center for Celiac Research at the University of Maryland has found that the incidence of celiac disease a particular set of 3,500 people in the  US has doubled every 15 years since 1974, as the participants get older.

Celiac disease is an autoimmune disease with a strong genetic component, involving an intolerance of gluten found in wheat, rye and barley.

This US study mirrors Finnish findings that people can be tolerant for years before developing the disease.

By testing markers in the blood, the US team found 1 in 501 people had celiac disease in 1974, 1 in 219 in 1984, and 1 in 133 in 2003.  Old people were around two and a half times more likely to have it than those younger, indicating an interaction between genetics and the environment.

Interestingly, only 11% of those with blood markers had actually been diagnosed with celiac disease. Classic symptoms are gastrointestinal (bloating, constipation, diarrhoea, nausea), but atypical symptoms include joint pain, chronic fatigue and depression.

September 27, 2010 Posted by | Aging, Celiac (coeliac) disease, Diet, Epigenetics, Genetics, Gluten, Health, Success | Leave a comment

Autism breakthrough.

Dr Valerie W Hu and colleagues have made a breakthrough in autism, by studying genetic expression in identical twins where only one has autism, and in identical twins with autism compared to siblings without it.

Since identical twins have the same genes, Hu was looking at epigenetics (epi meaning over or above). The team investigated differences in DNA methylation in the twins.

DNA methylation is involved in many functions including gene transcription, nervous system development, cell death/survival, and other biological processes implicated in autism. It is also known to play a role in many cancers.

Hu found 2 genes involved in this type of autism. BCL-2 was already known, but RORA is linked to autism for the first time.

Hu confirmed the genetic test by examining tissue samples from brain regions involved in autism.

Apart from finding that RORA is involved, Hu’s work opens up 2 interesting avenues.

First, the existence of a genetic test means people can be checked to see if they have this type or not, leading to appropriate personalised treatment.

Second, the DNA methylation route is already being tackled successfully in some cancers, which raises the hope that treatment can be developed to reverse this form of autism.

Hu’s work appears in the FASEB Journal.

April 9, 2010 Posted by | Autism, BCL-2, Brain, DNA test, Epigenetics, Genetics, RORA, Science, Valerie W Hu | 1 Comment