An interesting article published in Nature this week looked at how the role of diet in males affects the health of their daughters. In particular it looked at how male obesity can predispose to one’s offspring’s likelihood of developing diabetes.

What has this got to do with brain health? Well a lot, because obesity and diabetes are both risk factors for cognitive impairment and dementia.
The incidence of both obesity and type 2 diabetes is increasing at an alarming rate in western society. This study is a warning that not only are we harming ourselves, we are also harming our children.

Keeping things in perspective, firstly this is a study that was done on rats not humans, so we can’t say for definite that this would apply to us. But the suggestion is strong. Secondly because this was a study, the male rats were fed a high fat diet over a specified amount of time. Again from a human perspective, we don’t know whether these outcomes would follow on from a lifetime of poor eating habits or whether even short-term poor food choices around the time of conception could be important.

The study poses some interesting questions and may lead to a better understanding of what causes type-two diabetes.

Previous studies have looked at the effect of maternal diet and obesity on their offspring. Now it looks as if Dads too may need to be mindful of the impact that their lifestyle choices could have on their children.

Professor Margaret Morris researcher in Obesity and Diabetes at the University of new South Wales Sydney led this study. Her findings suggest that epigenetic alterations to our genes can lead to changes that are then expressed in our children.

In this study one group of male rats were fed a high fat diet. A control group received a normal diet. The high fat group became obese and developed signs of insulin resistance which is a precursor to diabetes. They were then mated with healthy weight female rats. The daughters of the fat group were found to have changes in their pancreas gland (where insulin hormone is produced) that were likely to produce problems with sugar regulation. These changes were not found in the daughters of the control group.

Professor Morris commented that today many mothers are entering pregnancy either overweight or obese and similarly it is likely that many obese men will father children.

My take on this from a healthy brain perspective is that while we can’t change our genes or prevent ageing to protect our brains, we can change our lifestyle and environment.
By choosing to keep to a healthy weight and avoiding type 2 diabetes we are not only contributing to our own health and brain fitness it would appear we are also protecting the health and brains of our children.
And Dads, it looks as if it’s up to you as well.

· Ng, S-F . et al. Nature 467, 963-966 (2010).
· Wang, Y. & Lobstein, T. Int. J. Pediatr. Obes. 1, 11-25 (2006).
· Morris, M. J. Expert Rev. Endocrinol. Metab. 4, 625-637 (2009).

Of all the risk factors for dementia and impaired cognitive function, diabetes and obesity have to be the two most important issues that we need to deal with now.
The burgeoning incidence of obesity and diabetes in the community and especially in young people is frightening. These young people are not just at increased risk of cardiovascular disease, cancer, and premature death. They have a far greater risk of developing cognitive impairment and dementia as adults.

What were the recent findings?

A study published in the July 30th issue of Diabetologia, reported that MRI brain scans of obese kids with type 2 diabetes show brain abnormalities, and on mental testing reduced cognitive performance. These kids will be functioning less well academically at school.

The study looked at a group of 18 obese adolescents with type 2 diabetes and another group of similarly obese adolescents who hadn’t yet developed significant insulin resistance or type 2 diabetes.
This is the first time that cognitive deficits as a consequence of obesity with diabetes have been shown in this age group. Previous studies have looked at older people where similar abnormal brain findings on scans had been attributed to be the result of vascular disease, rather then a direct effect on the brain by the diabetes itself.

Both groups of adolescents came from similar socio-economic backgrounds and ethnicity.

They were asked to complete some mental tests. The results of group with diabetes were significantly lower in the areas of memory, spelling and overall academic function. They also showed white matter abnormalities on brain scans.

Dealing with insulin resistance may be the key.

The results highlight the urgent need to address both obesity and diabetes. More and larger studies need to be undertaken to verify these findings and to then get government and health professional support so that effective health programs can be developed and implemented to deal with this rising tide of obesity and diabetes. The challenge will be to be able to help kids already diagnosed with insulin resistance, to improve their insulin sensitivity through weight management, healthy eating and exercise.

A separate study published in August, looked at the relationship between insulin resistance, type 2 diabetes and the development of plaques in the brain. Brain plaques are associated with the neurodegenerative disease of Alzheimer’s. Insulin resistance has been described as a pre-diabetic state. In insulin resistance, the insulin hormone our body produces is becomes less effective in exerting its effect on helping to lower the blood sugar to normal. This study followed an older population of 135 Japanese subjects aged over 67 years over a period of 10 to 15 years. They underwent several glucose tolerance tests to measure their blood sugar levels and were monitored for symptoms of Alzheimer’s disease over that time. After their deaths their brains were autopsied and it was found that those who had had at least three abnormal glucose tolerance tests had a greater risk of developing plaques in their brain. In other words, having insulin resistance was associated with an increased likelihood of the person developing brain plaques that are commonly found in patients with Alzheimer’s disease. Further studies will now need to be undertaken to see whether insulin resistance is associated as being a cause of this plaque formation.

The real risk of failing to take action now.

If we continue to fail to address the issues society currently has in terms of the level of our overall inactivity, obesity and diabetes then I believe we are setting ourselves up to add to the already significant social and economic burden of increasing rates of dementia we are anticipating over the next few decades.
It won’t just be the baby boomers that are at risk of dementia simply because of their increasing age. We have yet to count the impact of younger people already burdened with the significant health impairment of obesity and diabetes that will be adding to this toll.

References:

P.L. Yau, D.C. Javier, C.M. Ryan, W.H. Tsui, B.A. Ardekani, S. Ten and A. Convit. Preliminary evidence for brain complications in obese adolescents with type two diabetes mellitus. Diabetologica,2010;DOI; 10.1007/s00125-010-1857-y

T.Matsuzaki, K. Sasaki, Y.Tanizaki, J. Hata, K. Fujimi, Y. Matsui, A. Sekita, S.O. Suzuki, S. Kanba, Y. Kiyohara, and T. Iwaki. Insulin resistance is associated with the pathology of Alzheimer’s disease. The Hisayama Study. Neurology,2010;DOI:10.1212/WNL.0b013e3181eee25f

Statisticians have been telling us how Western societies are facing a tsunami of people developing dementia and Alzheimer’s over the next couple of decades. This is associated with our ageing population; we are all living longer, so our relative risk of developing dementia rises as well.

What worries me though is the fact that we seem to be ignoring the impact that the dramatic increase in people living with Type 2 diabetes and obesity will have on these figures.

Both diabetes and obesity are known risk factors for dementia.
Adults who develop diabetes before the age of 65 have twice the risk of developing dementia compared to non-diabetics and also have an increased risk of depression.

It is our children that worry me the most. Twenty years ago the number of kids diagnosed with Type 2 diabetes was in the order of 2%. It was an extremely rare condition. Now 30 to 50% of all those diagnosed with Type 2 diabetes are between the ages of 9 and 19 years. Those aged in their thirties, have seen a 70% increase in the number of people diagnosed.
The scary thing also, is that it is known that there are an even greater number of people with undiagnosed diabetes in the general population.

What is Type 2 diabetes?

When we eat a meal, the carbohydrates in it are broken down and released into our blood stream as sugar, leading to an increase in the blood sugar level. This then stimulates the pancreas gland to release insulin hormone which works to restore the blood sugar level back to normal by sending the glucose to tissues that need it for energy, or for storage. If the body is repeatedly overloaded with excess glucose, the body’s ability to respond to the insulin is diminished, leading to a condition called insulin resistance. Increasing amounts of insulin then get produced, but it can no longer exert its effect. This is the condition of Type 2 diabetes where blood sugar levels are consistently too high and associated with elevated insulin levels.

It is distinguished from Type 1 diabetes where the specialised glands in the pancreas are unable to produce insulin.

When are we going to wake up to this risk?

If you have diabetes, you have a higher risk of cognitive decline and dementia.

In a study of 2300 older women aged 70 to 78, non-diabetics on mental testing scored twice as high as diabetics. It was also found that the longer the person had had diabetes, the more poorly she performed.

In another multiethnic, multicenter study of 10,000 people, the results of cognitive tests taken 6 years apart were compared. In the 40 to 70 year age group, diabetes was again linked to greater cognitive decline.

What does diabetes do to the body and brain?

Diabetes affects multiple organs in the body including the blood vessels, heart eyes, brain and kidneys and is insidious in how it gradually erodes cognitive ability. Elevated blood sugar levels contribute to hardening of the arteries, (atherosclerosis) which increases the risk of heart disease and stoke. In the brain, this vascular damage is linked to an increase in small infarcts (injury to small arterioles in the brain) or tiny strokes. Having persistently elevated blood sugar contributes to damage of our brain cells, brain atrophy and cognitive impairment. The loss of brain cells is especially prominent in the area of the hippocampus, the specialised brain area concerned with memory and learning.
Diabetic patients who have developed diabetic retinopathy have been shown to have twice the risk of developing cognitive impairment.

Excess insulin also contributes to the brain damage. It has been discovered that the brain has it’s own insulin receptors. Increased insulin levels have been linked to increased levels of amyloid, the protein associated with plaques found in Alzheimer’s. Excess insulin also has a role in stimulating inflammation, and reducing the levels of acetylcholine an essential neurotransmitter for memory.

But it’s not just diabetics who are at risk of impaired brain function and reduced mental performance. It has been shown that drinking a sugary glucose drink will adversely affect your ability to perform memory tests. So the key is to avoid big swings in blood sugar levels.

Because we know that diabetes is associated with an increase risk of cognitive impairment and dementia, it is vital that the message gets out to all those at risk.

The good news though, is that we know that good lifestyle choices can have a hugely beneficial effect on blood sugar control.

The aim is to

• Keep blood sugar levels in the normal range
• Maintain a healthy body weight
• Eat a nutritious and brain healthy diet low in saturated fat
• Exercise for 30 minutes a day by walking or other moderate intensity activity.

My question to you is this. Can we afford not be taking immediate steps to educating people to fully understand the consequences of “accepting” the recent global increases in obesity and diabetes?

Our sweet tooth is killing our brain.

Refs:
Roberts et al. Association of Duration and Severity of Diabetes Mellitus With Mild Cognitive Impairment. Archives of Neurology, 2008; 65 (8): 1066 DOI: 10.1001/archneur.65.8.1066
University of Southern California (2009, January 28). Getting Diabetes Before 65 More Than Doubles Risk For Alzheimer’s Disease.