Wednesday, January 01, 2014

'Bad' cholesterol that causes heart attacks now linked to Alzheimer's: Clumps stick to brain cells affecting memory and mood

But note that statins did no good -- as usual:  "No association was found between statin use and PIB index, and controlling for cholesterol treatment in the statistical models did not alter the basic findings."

The ‘bad’ type of cholesterol – which causes heart disease – is linked to Alzheimer’s, researchers have found.

Such cholesterol has previously been associated with a narrowing of the arteries.

Now a study has revealed that the bad type is related to the amyloid peptide protein in the brain, which is present in Alzheimer’s.
A study has revealed that the bad type of cholesterol - which causes heart disease - is related to the amyloid peptide protein (pictured) in the brain, which is present in Alzheimer's

A study has revealed that the bad type of cholesterol - which causes heart disease - is related to the amyloid peptide protein (pictured) in the brain, which is present in Alzheimer's

In patients affected by disease, clumps of the protein stick to brain cells, affecting memory, mood and behaviour.

The discovery may explain the well-known link between raised cholesterol and an increased risk of Alzheimer’s.

Researchers found the link depended on whether people had more good cholesterol, known as high density lipoprotein (HDL), or the bad form called low density lipoprotein (LDL).

High levels of LDL can lead to narrowed arteries and heart disease, whereas HDL is protective.

The new US research suggests the two kinds of cholesterol have the same effect on the brain as on the heart.

Study leader professor Bruce Reed, from the University of California at Davis, said: ‘Unhealthy patterns of cholesterol could be directly causing the higher levels of amyloid known to contribute to Alzheimer’s, in the same way that such patterns promote heart disease.’

The scientists looked at 74 men and women aged 70 and over. All had brain scans using a tracer chemical that binds with amyloid plaques in order to highlight them on the images.

Higher fasting levels of LDL and lower levels of HDL were both associated with more amyloid in the brain, according to the findings published online in the journal JAMA Neurology.

Professor Reed said: ‘This study provides a reason to certainly continue cholesterol treatment in people who are developing memory loss, regardless of concerns regarding their cardiovascular health.’

Fellow author Dr Charles DeCarli said the discovery was a ‘wake-up call’ for those with a poor cholesterol balance.

Dr Laura Phipps, of Alzheimer’s Research UK, said: ‘The findings add to existing evidence that cholesterol could play a role in the Alzheimer’s disease process.

‘The best way to keep our brain healthy is to eat a balanced diet, maintain a healthy weight, not smoke, exercise regularly  and keep blood pressure and cholesterol  in check.’


Associations Between Serum Cholesterol Levels and Cerebral Amyloidosis

Bruce Reed et al


Importance Because deposition of cerebral β-amyloid (Aβ) seems to be a key initiating event in Alzheimer disease (AD), factors associated with increased deposition are of great interest. Whether elevated serum cholesterol levels act as such a factor is unknown.

Objective To investigate the association between serum cholesterol levels and cerebral Aβ during life early in the AD process.

Design, Setting, and Participants A multisite, university medical center–based, cross-sectional analysis of potential associations between contemporaneously assayed total serum cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and cerebral Aβ, measured with carbon C11–labeled Pittsburgh Compound B (PIB) positron emission tomography. Seventy-four persons (mean age, 78 years) were recruited via direct outreach in stroke clinics and community senior facilities following a protocol designed to obtain a cohort enriched for cerebrovascular disease and elevated vascular risk. Three patients had mild dementia. All others were clinically normal (n = 33) or had mild cognitive impairment (n = 38).

Results Cerebral Aβ was quantified using a Global PIB Index, which averages PIB retention in cortical areas prone to amyloidosis. Statistical models that controlled for age and the apolipoprotein E ε4 allele revealed independent associations among the levels of LDL-C, HDL-C, and PIB index. Higher LDL-C and lower HDL-C levels were both associated with a higher PIB index. No association was found between the total cholesterol level and PIB index. No association was found between statin use and PIB index, and controlling for cholesterol treatment in the statistical models did not alter the basic findings.

Conclusions and Relevance Elevated cerebral Aβ level was associated with cholesterol fractions in a pattern analogous to that found in coronary artery disease. This finding, in living humans, is consistent with prior autopsy reports, epidemiologic findings, and animal and in vitro work, suggesting an important role for cholesterol in Aβ processing. Because cholesterol levels are modifiable, understanding their link to Aβ deposition could potentially and eventually have an effect on retarding the pathologic cascade of AD. These findings suggest that understanding the mechanisms through which serum lipids modulate Aβ could offer new approaches to slowing Aβ deposition and thus to reducing the incidence of AD.

JAMA Neurol. Published online December 30, 2013

Why those 'superfruits' may just be a costly rip-off... and you’d do just as well eating a humble potato!

Is the antioxidant religion faltering at last?

Believe the hype and they’re the natural solution for everything from cancer, heart disease and dementia to ageing skin, poor eyesight and insomnia.

No wonder ‘superfruits’ pop up in cereals, desserts, snack bars, juice, face cream — even designer gin.

But though it is claimed that goji berries, acai juice, pomegranates and cranberries are rooted in  ancient medicine, the explosion in their use is, in fact, a modern phenomenon.

Two out of three juices launched last year claimed to contain superfruit. A major launch in 2011 was Cherrygood — a fruit juice made in part from an imported American cherry supposedly very high in antioxidants.

One glass will give ‘the equivalent health benefits of around 20 portions of fruit and vegetables’. Though the company offers no proof of that claim, Cherrygood has been a hit, with all supermarkets and health stores stocking it.

But anti-obesity campaigners point out it has as much sugar as cola — about 5 tsp in a 250ml serving. Cherrygood Plus has 9 tsp sugar.

Despite doubts around the science, superfruits and their spin-offs keep coming. Last year saw the launch of a ‘supertree’ — the powder of the bark of the African baobab, which you mix into yoghurt or water to get ‘six times more vitamin C than oranges’.

Meanwhile, Waitrose is busy pushing yuzu lemonade, from a Japanese citrus fruit that has ‘three times as much vitamin C as lemons’.

Sales are soaring of fibre and potassium-rich goldenberries, a dried version of the South American cape gooseberry.

Predicted for success in 2014 is the gac fruit from Vietnam, a spiky orange with flesh that looks like raw meat. It contains lycopene — an antioxidant also found in tomatoes — which is said to combat prostate cancer.

Also coming up is the Chilean wineberry, a miniature blueberry from Patagonia, with ‘three to four times more antioxidants than goji berries’.

Most of these fruits are sold dried or as juice — transporting fresh fruit raises costs. The nutrients will not be damaged if the drying is done carefully, but some, such as cranberries, are sprayed with sugar as part of the process.

Most juice versions of superfruits contain extra sugar in the form of concentrated apple or grape juice, which still allows them to claim ‘no added sugar’.

Still it seems that if eaten or drunk in moderation, none of the superfruits will do you any harm. But will they do you any good?

All the superfruits claim they contain a big dose of vitamin C, but the simple fact is that there are no diseases prevalent in Britain that have anything to do with vitamin C deficiency.

Many foods have vitamin C, including bread and jam, because acids containing it are often used as a preservative.

The skin of a medium-sized potato will give you 45 per cent of the daily recommended dose.

Taking extra vitamin C is not believed to do much good, despite the popular belief that it fends off colds and flu.

A review of 30 studies in 2007 concluded that the benefits of taking vitamin C supplements for such illnesses were not worth the expense.

Sioned Quirke, a senior dietitian for the NHS in Wales, says: ‘We often find that people who can afford to buy these products are following a healthy, balanced diet and do not need additions. And they are painfully expensive.’

She believes the poor and unhealthy are being taken advantage of, citing one patient spending £75 or more on food supplements in a health shop. These included dried superfruits and juices, which can cost as much as £20 a litre. ‘People are gullible, especially when they are desperate for a miracle cure. These shops prey on them. Some people will be living on crisps for the next week because they can’t afford a proper diet.’

So, is there anything in the superfruit claims?

The most interesting evidence is around polyphenols and bioflavonoids, found in large amounts in superfruits. These are forms of antioxidants, as is vitamin C.

Oxidation produces harmful agents called free radicals that are blamed for a host of problems, from the formation of cancers to ageing. Half of all Americans are said to take antioxidant supplements.

But though millions have been spent over two decades researching antioxidants, the science is still far from convincing.

Cancer experiments have shown positive results, but only in lab animals. The most impressive study of berries and disease — carried out by Harvard University on 93,000 women for 18 years — did find that those who ate three portions of strawberries and blueberries a week had 34 per cent less  chance of having a heart attack than those who had one portion a month.

Researchers speculated antioxidants in the berries might play a role, but so might lifestyle. Women who rarely eat fruit are also less likely to take exercise.

One of Britain’s top toxicologists, Professor David Colquhoun, of University College, London, says that in the case of the antioxidant beta-carotene and vitamin E supplements, studies show these are more likely to raise your risk of dying early. A major review of studies in 2012 concluded there was not enough evidence to support people taking antioxidant supplements.

Professor Colquhoun told me he has never read any science on nutrition that has persuaded him to alter his already healthy diet.

His stark verdict is: ‘Antioxidants are useless, and some are dangerous.’

Government regulators agree their beneficial effects have not been proved. In Europe and the U.S., food safety agencies have moved to try to limit manufacturers’ claims — though with little effect, as any health food website will show.

Shops are more careful — Holland & Barrett, Britain’s largest health chain, stocks 114 products that contain antioxidants. But the store only says these ‘may help’ rather than claiming specific benefits.

Some say the best effect of superfruits may take place a long way from the bodies of those who buy them.

The fashion for goldenberries, a high-potassium, high-fibre fruit sold in Marks & Spencer, Whole Foods and Holland & Barrett, is bringing employment to poor farmers in the Andes. Growing coca for cocaine is the only other valuable crop.

‘All fruits are superfruits in their own way,’ says Sioned Quirke. ‘None is going to guide you to the Promised Land, but try to meet the five-a-day fruit and veg aim by eating a variety of whole fruits — not just juices, which often are just sugar and flavour — and you’ll begin to optimise your health.’


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