Wednesday, November 03, 2010

Fish oil pills 'do not stop the march of Alzheimer's', new study shows

Fish oil capsules do not slow ­mental or physical decline in Alzheimer’s patients, say researchers. The ‘memory-boosting’ supplements did not affect progression of the disease at any stage, a £7million study has found.

The increased belief in fish oil’s powers of protection against degenerative brain disease has spawned a multi-million-pound industry. But the U.S. study’s lead researcher Dr Joseph Quinn, of ­Oregon Health and ­Science University, said: ‘We had high hopes that we’d see some efficacy but we did not.’

Fish oil supplements, rich in the omega-3 fatty acids DHA and EPA, are known to benefit brain function and some previous trials had suggested they could slow or prevent mental decline in Alzheimer’s.

In the latest study, almost 400 men and women with an average age of 76 and mild to moderate Alzheimer’s were randomly assigned to take either 200mg DHA pills or dummy pills daily for 18 months.

DHA occurs naturally in the brain but is found in reduced amounts in people with Alzheimer’s disease.

The trial found similar rates of physical and mental decline in both groups using scoring systems and MRI brain scans. Supplements did not slow the development of Alzheimer’s even in a subgroup of patients with the mildest symptoms.

‘There is no basis for recommending DHA supplementation for patients with Alzheimer’s disease,’ says a report in the Journal of the American Medical Association.

Supporters of fish oil’s benefits pointed out that the latest study did not investigate whether supplements could ward off the onset of Alzheimer’s in the first place.

Experts said attempting to reverse the disease after symptoms appear may be too late, as the underlying process that causes Alzheimer’s begins years, if not decades, before diagnosis.

Dr Kristine Yaffe, a dementia researcher at University of California at San Francisco, said that previous trials had shown omega-3 supplements were ‘associated with reduced risk of developing Alzheimer’s disease’ but trials on their use in those who already had the disease failed to show any impact.

Laurie Ryan, programme director of Alzheimer’s studies at the U.S. National Institute on Aging, said the results were discouraging.

But independent dietitian Dr Carrie Ruxton from the Health Supplements Information Service said a recent study found high-dose supplements of DHA improved memory and learning in 485 older adults with age-related cognitive decline. She said: ‘Looking at the broader range of clinical trial evidence it appears that DHA could have a beneficial effect on cognitive function in people with milder Alzheimer’s disease or earlier cognitive decline.

‘In the current study, DHA may have been given too late in the disease process to produce benefit. ‘It is also important to note that the authors themselves concluded that an intervention with DHA might be more effective if initiated earlier in the course of the disease in patients who do not have overt dementia.’

Omega-3 fatty acids in fish or supplements have been shown to help protect against heart disease and are being studied for possible effects on a range of other illnesses, including cancer and depression.


Everything you thought you knew about food is WRONG

There is much truth in the iconoclasm below but I would like to see more evidence on some of the claims

We think we know what to eat: less red meat and more fibre, less saturated fat and more fruit and veg, right? Wrong, according to a controversial new book by obesity researcher and nutritionist Zoe Harcombe.

In The Obesity Epidemic: What Caused It? How Can We Stop It? Harcombe charts her meticulous journey of research into studies that underpin dietary advice — and her myth-busting conclusions are startling.

Myth: The rapid rise in obesity is due to modern lifestyles

According to Zoe Harcombe, the ­obesity epidemic has less to do with our lifestyles than with what we are eating. ‘The key thing that people don’t realise is that throughout history, right until the Seventies, obesity levels never went above 2 per cent of the population in the UK,’ she says. ‘Yet by the turn of the millennium, obesity levels were 25 per cent.

‘What happened? In 1983, the government changed its diet advice. After that, if you look at the graphs, you can see obesity rates taking off like an aeroplane. You might feel it is coincidence, but to me it is blindingly obvious.

‘The older dietary advice was simple; foods based on flour and grains were ­fattening, and sweet foods were most ­fattening of all.

‘Mum and Granny told us to eat liver, eggs, sardines and to put butter on our vegetables. The new advice was “base your meals on starchy foods” — the things that we used to know made us fat (rice, pasta, potatoes and bread). That’s a U-turn.’

Myth: Starchy carbohydrates should be the main building blocks of our diet

We’ve been told that carbohydrates such as rice, pasta, bread and potatoes should form the bulk of what we eat. The trouble with this, says Zoe Harcombe, is that as carbs are digested, they are broken down into glucose.

This process makes your body produce insulin, in order to deal with the extra glucose. One of insulin’s main roles in the body is fat storage, so whenever you eat carbs, you are switching on your body’s fat-storing mechanism. Whatever carbs you don’t use up as energy will be quickly stored away in the body as fat.

We should get back to doing as nature intended and eat real, unprocessed food, starting with meat, fish, eggs, vegetables and salads.

Myth: Losing weight is about calories in versus calories out

‘If only it were that simple,’ says ­Harcombe. ‘People think that if they cut out 500 calories a day, they will lose 1lb a week. ‘They might at first, but then the body will recognise that it is in a state of ­starvation and turn down its systems to conserve energy. ‘So you may be putting fewer calories in, but at the same time you will be using up fewer calories to get through the day.

‘Losing weight is more a question of fat storage and fat utilisation. You need the body to move into a fat-burning mode and, to do that, you need to cut down your consumption not of calories, but of carbohydrates.’

Myth: More exercise is a cure for the obesity epidemic

This is standard wisdom; exercise, we think, will burn calories, lose fat and speed up our metabolism. Think again, says ­Harcombe.

‘If you push yourself into doing extra exercise, it will be counterproductive because you will get hungry — your body will be craving carbohydrate to replenish its lost stores. ‘If you are trying to control weight, it is so much easier to control what you put into your mouth. Not how much, but what. Then it doesn’t matter what you do or don’t do by way of exercise.’

Myth: Fat is bad for us

‘Real fat is not bad for us,’ says ­Harcombe. ‘It’s man-made fats we should be demonising. Why do we have this idea that meat is full of saturated fat? In a 100g pork chop, there is 2.3g of unsaturated fat and 1.5g of saturated fat.

‘Fat is essential for every cell in the body. In Britain [according to the Family Food Survey of 2008], we are deficient in the fat-soluble vitamins A, D and E, which are responsible for healthy eyesight, bone strength, mental health, cancer and blood vessel protection and, therefore, heart health. We need to eat real fat in order for these vital vitamins to be absorbed into the body.’

Myth: Saturated fat causes heart disease

Over the past 50 years, we have accepted this as one of the basic nutritional truths. But Zoe Harcombe says: ‘No research has ever properly proved that eating ­saturated fat is associated with heart disease, let alone that it causes it.’

Myth: Cholesterol is a dietary enemy

Controversially, Harcombe does not consider ‘high’ cholesterol levels a bad thing! ‘To pick a number — 5 (mmol/l) — and to say everyone should have cholesterol levels no higher than this is like declaring the average height should be 5ft 4in and not 5ft 9in and medicating everyone who doesn’t reach this meaningless number to reduce their height. It really is that horrific.

‘Ancel Keys, who studied cholesterol extensively in the Fifties, said categorically that cholesterol in food does not have any impact on cholesterol in the blood.

‘What is abnormal is the amount of ­carbohydrate we eat, especially refined carbohydrate, and this has been shown to determine triglyceride levels — the part of the cholesterol reading your GP may be most concerned about.

‘It’s the ultimate irony. We only told ­people to eat carbs because we demonised fat and, having picked the wrong villain, we are making things worse.’

Myth: We should eat more fibre

For three decades, we have crammed fibre into our bodies to help us feel full and keep our digestive systems moving. This is not a good idea, says Harcombe.

‘The advice to eat more fibre is put forward along with the theory that we need to flush out our ­digestive systems. But essential minerals are absorbed from food while it is in the intestines, so why do we want to flush everything out? Concentrate on not putting bad foods in.’

Myth: You need to eat five portions of fruit and veg a day
Variety of fruit and vegetables.

‘Five-a-day is the most well-known piece of nutritional advice,’ says ­Harcombe. ‘You’d think it was based on firm evidence of health benefit. Think again!

‘Five-a-day started as a marketing campaign by 25 fruit and veg companies and the American National Cancer Institute in 1991. There was no evidence for any cancer benefit.’

Myth: Fruit and veg are the most nutritious things to eat

Apparently not. Harcombe allows that vegetables are a great addition to the diet — if served in butter to deliver the fat-soluble vitamins they contain — but ­fructose, the fruit sugar in fruit, goes straight to the liver and is stored as fat.

Fruit is best avoided by those trying to lose weight, says Harcombe, who adds: ‘Vitamins and minerals in animal foods — meat, fish, eggs and dairy products — beat those in fruit hands down.’

Myth: Food advisory bodies give us sound, impartial advice

The organisations we turn to for advice on food are sponsored by the food industry. The British Dietetic Association (BDA), whose members have a monopoly on delivering Department of Health and NHS dietary advice, is sponsored by Danone, the yoghurt people, and Abbott Nutrition, which manufactures infant ­formula and energy bars.

The British Nutrition Foundation, founded in 1967 to ‘deliver authoritative, evidence-based information on food and nutrition in the context of health and lifestyle’, has among its ‘sustaining members’ British Sugar plc, Cadbury, Coca-Cola, J Sainsbury PLC and Kraft Foods.

‘When the food and drink industry is so actively embracing public health advice, isn’t it time to wonder how healthy that advice can be?’ says Harcombe.


No comments: