Thursday, January 02, 2014
Sugar: How sweet it is ... and how bad it is
This is just a reprise of the old Robert Lustig crusade. Very few medical researchers agree with him -- as the overall evidence is far from clear
Hormones drive the development of breast and buttock fat in women at puberty. They drive hunger during pregnancy. Is it really so unlikely that they could also drive how much we eat, how much we exercise, and how much we store as fat?
We don't need to look far to find the hormones involved. Insulin, and its partner leptin, drive the packing and unpacking of fat cells and the signals that tell our brain it has had enough and is no longer hungry. Each responds to sugar.
And please don't tell me sugar is "a natural part of life", as the ads used to say. In his massively viewed YouTube lecture Sugar: The Bitter Truth, childhood obesity expert Robert Lustig makes the point that until relatively recently pure sugar was inaccessible, protected by either fibre (sugar cane is extraordinarily tough) or bees.
Ordinary sugar is half glucose and half fructose. There are about 16 teaspoons in a 600 millilitre drink. The glucose triggers a surge of insulin that packs fatty acids into fat cells and temporarily prevents them getting out. It also directs glucose to muscles where it is stored as glycogen. The fructose helps build insulin resistance and also resistance to leptin, the chemical messenger that turns off the feeling of hunger. The greater our exposure to fructose, the longer we feel hungry and the more insulin we produce, directing fat to our fat cells (fructose itself is turned into fat).
Lustig says Americans are producing twice the insulin they were 25 years ago.
None of this would matter much if it was merely making us big, but it is also driving high blood pressure, strokes and heart attacks. It's helping kill us.
Australia's soft drink industry is wrong when it says "all kilojoules matter, it doesn't matter where those kilojoules come from". Some drive hunger itself, making the "federal budget" approach of eating less and exercising more extraordinarily difficult.
Until recently the National Health and Medical Research Council was relatively unconcerned. Its dietary guidelines advised that "a moderate amount of sugar in daily meals is not a problem …
"In fact, spreading a little jam on wholemeal bread or sprinkling a little sugar to wholegrain breakfast cereal can make these nutritious foods more enjoyable to eat."
Not now. The new guidelines issued in February for the first time tell Australians to limit their consumption of "foods and drinks containing added sugars such as confectionery, sugar-sweetened soft drinks and cordials, fruit drinks, vitamin waters, energy and sports drinks".
Vitamin E may slow Alzheimer's disease
Very limited results
RESEARCHERS say vitamin E might slow the progression of mild-to-moderate Alzheimer's disease - the first time any treatment has been shown to alter the course of dementia at that stage.
In a study of more than 600 older veterans, high doses of the vitamin delayed the decline in daily living skills, such as making meals, getting dressed and holding a conversation, by about six months over a two-year period.
The benefit was equivalent to keeping one major skill that otherwise would have been lost, such as being able to bathe without help. For some people, that could mean living independently rather than needing a nursing home.
Vitamin E did not preserve thinking abilities, though, and it did no good for patients who took it with another Alzheimer's medication. But those taking vitamin E alone required less help from caregivers - about two fewer hours each day than some others in the study.
"It's not a miracle or, obviously, a cure," said study leader Dr Maurice Dysken of the Minneapolis VA Health Care System. "The best we can do at this point is slow down the rate of progression."
The US Department of Veterans Affairs sponsored the study, published on Tuesday by the Journal of the American Medical Association.
No one should rush out and buy vitamin E, several doctors warned. It failed to prevent healthy people from developing dementia or to help those with mild impairment ("pre-Alzheimer's") in other studies, and one suggested it might even be harmful.
Still, many experts cheered the new results after so many recent flops of once-promising drugs. "This is truly a breakthrough paper and constitutes what we have been working toward for nearly three decades: the first truly disease-modifying intervention for Alzheimer's," said Dr Sam Gandy of Mount Sinai School of Medicine in New York. "I am very enthusiastic about the results."
About 35 million people worldwide have dementia, and Alzheimer's is the most common type. In the US, about 5 million have Alzheimer's. There is no cure and current medicines just temporarily ease symptoms.
Researchers don't know how vitamin E might help, but it is an antioxidant, like those found in red wine, grapes and some teas. Antioxidants help protect cells from damage that can contribute to other diseases, says the federal Office on Dietary Supplements.
Many foods contain vitamin E, such as nuts, seeds, grains, leafy greens and vegetable oils. There are many forms, and the study tested a synthetic version of one - alpha-tocopherol - at a pharmaceutical grade and strength, 2000 international units a day.
Posted by jonjayray at 12:10 AM