Monday, July 12, 2010

Exercise may be best way to fight Alzheimer's

Advances in detection show need for better drugs to prevent disease, scientists say

Associated Press

MILWAUKEE, Wisconsin — Scientists are reporting advances in detecting and predicting Alzheimer's disease at a conference in Honolulu this week, plus offering more proof that getting enough exercise and vitamin D may lower your risk.

There are better brain scans to spot Alzheimer's disease. More genes that affect risk. Blood and spinal fluid tests that may help tell who will develop the mind-robbing illness and when.

But what is needed most — a treatment that does more than just ease symptoms — is not at hand.

"We don't have anything that slows or stops the course," said William Thies, the Alzheimer's Association scientific director. "We're really in a silent window right now" with new drugs, he said.

Several promising ones flopped in late-stage tests — most recently, Pfizer Inc.'s Dimebon. Results on several others won't be ready until next year.

Still, there is some progress against Alzheimer's, a dementia that afflicts more than 26 million people worldwide. Highlights of the research being reported this week:

•Prevention. Moderate to heavy exercisers had half the risk of developing dementia compared with less active people, researchers from the long-running Framingham Heart Study reported Sunday. Earlier studies also found exercise helps.

"That seems to be as good as anything" for preventing dementia, said Dr. Richard Mayeux, a Columbia University neurologist and conference leader.

Another big government-funded study found that vitamin D deficiency can raise the risk of mental impairment up to fourfold. This doesn't mean taking supplements is a good idea, doctors warn. A large study is testing whether that is safe and helps prevent a variety of diseases.

•Novel treatments. Tests of an insulin nose spray to improve cognition gave encouraging results, but "it's still a pilot trial" and larger studies are needed to see if this works and is safe, said Laurie Ryan. She oversees Alzheimer's study grants for the National Institute on Aging, which funded the work.

It's based on the theory that Alzheimer's and diabetes are related. Diabetics seem to have a higher risk of developing Alzheimer's, and Alzheimer's patients tend to have insulin resistance, Ryan said. Giving insulin as a nose spray sends it straight to the brain without affecting blood-sugar levels, she explained.

"If it works, it would certainly be an easy thing to administer. It's not like taking a shot each day," and likely would be cheap, she said.

•Improved detection. Many types of imaging can document dementia, which usually is diagnosed through cognition tests. For several years, scientists have used one such method — a radioactive dye and PET scans — to see the sticky brain plaque that is a key feature of Alzheimer's. But the dye is tough to use, and at least four companies are developing better ones.

Until there are better treatments, there will be little demand for tests that show you have or are destined to get the disease, several experts said. There's little testing now for the first gene strongly tied to Alzheimer's risk, ApoE-4.

"It's kind of like finding high cholesterol" but not having drugs that can lower it, said Dr. Mark Sager, director of the Wisconsin Alzheimer's Institute at the University of Wisconsin-Madison. He was involved in a study of a different Alzheimer's-linked gene that will be reported this week.
Scientists also don't know if the plaque is a cause, an effect, or just a sign of Alzheimer's. Two experimental drugs seemed to clear plaque but did not lead to clinical improvement.

"We've still got a long way to go," Sager said.

Vitamin D: The Sunshine Vitamin

Why UVB from sunlight is the most effective, the most reliable, the most abundant, and the most natural source for Vitamin D


Sun exposure to the skin is the human race’s natural, intended, most effective and most neglected source of vitamin D.

Vitamin D sufficiency, along with diet and exercise, has emerged as one of the most important preventive factors in human health. Hundreds of studies now link vitamin D deficiency with significantly higher rates of many forms of cancer‚ as well as heart disease‚ osteoporosis‚ multiple sclerosis and many other conditions and diseases.

Because sunshine is a free commodity with no publicist or lobbyist, the Sunshine Vitamin Alliance is established as a coalition of right-minded physicians, individuals and organizations who advocate natural vitamin D production through regular, non-burning sun exposure.

•Humans make 90 percent of our vitamin D naturally from sunlight exposure to our skin – specifically, from ultraviolet B exposure to the skin, which naturally initiates the conversion of cholesterol in the skin to vitamin D3.

•Few foods naturally contain or are fortified with supplemental vitamin D. For example, an 8-ounce glass of whole milk is fortified with 100 IU (international units) of vitamin D – just 10 percent of what the most conservative vitamin D researchers now say we need daily. In contrast, sun exposure to the skin makes thousands of units of vitamin D naturally in a relatively short period of time.

•While vitamin D supplements are an alternative means of producing vitamin D when regular, non-burning sun exposure is not possible, oral supplementation of vitamin D is not nature’s intended means of producing this vitamin.

•While overexposure to sunlight carries risks, the cosmetic skin care industry has misled the public into believing that any UV exposure is harmful. No research has shown that regular, non-burning exposure to UV light poses a significant risk of skin damage.

•Humans spend less time in the sun today than at any point in human history – which is why more than 1 billion people worldwide are vitamin D deficient.

Vitamin D Comes From the Sun

Sunlight is the best and only natural source of vitamin D. Unlike dietary or supplementary vitamin D, when you get your ‘D’ from sunshine your body takes what it needs, and de-metabolizes any extra. That’s critical – as vitamin D experts and many health groups now advocate 1,000 to 2,000 IU of vitamin D daily – five to ten times the old recommendations. Because too much ‘D’ from dietary supplements may cause the body to over-process calcium, nobody really knows for sure how much supplementary vitamin D is safe. On the other hand, sunlight-induced vitamin D doesn’t have that problem – it’s the way your body is intended to make it!

Sunlight Exposure (full body exposure)* 3,000 – 20,000 IU
Salmon (3.5 oz. of fresh, wild salmon) 600 – 1,000 IU
Salmon (3.5 oz. of fresh, farmed salmon) 100 – 250 IU
Fortified Whole Milk, 8-oz. glass** 100 IU
Fortified Multi-vitamin 400 IU

Source: Holick, MF. Vitamin D Deficiency. New England Journal of Medicine, July 2007

* Sun exposure to the arms and legs for 10-15 minutes. The amount of vitamin D produced depends on the intensity of the UVB in the sun and many other factors. Darker-skinned individuals may need 5-10 times more exposure than a fair-skinned person to make the same amount of vitamin D. In northern climates sunlight is too weak in parts of the year to make any vitamin D – a period referred to as ‘Vitamin D Winter’.

** Vitamin D is supplemented into milk. It doesn’t occur naturally in milk.