Sometimes a little dirt may be good for you, right?


A new study suggests that those living in more industrialized countries with better hygiene may be more likely to develop Alzheimer's than those who don't. The reason? A lack of contact with bacteria, viruses and other microorganisms that can lead to problems with immune development and increased risk of dementia.


Indeed the new research has uncovered a "very significant" link between a nation's wealth and hygiene and the Alzheimer's "burden"[1] on its population.


Scientists say that the research gives even more credence to the "hygiene hypothesis" in relation to Alzheimer's: that sanitized environments in developed nations mean less exposure to a variety of bacteria, which could actually cause the immune system to develop poorly and expose the brain to the inflammation associated with Alzheimer's.


"The 'hygiene hypothesis', which suggests a relationship between cleaner environments and a higher risk of certain allergies and autoimmune diseases, is well-established. We believe we can now add Alzheimer's to this list of diseases," said Dr. Molly Fox,[2] who conducted the research at Cambridge's Biological Anthropology division, in a press release.


“There are important implications for forecasting future global disease burden, especially in developing countries as they increase in sanitation," she said.


After factoring in differences in population age structures, the study found that countries with higher levels of sanitation had higher rates of Alzheimer’s. For example, countries where all people have access to clean drinking water, such as the UK and France, have 9 percent higher Alzheimer’s rates than countries where less than half have access, such as Kenya and Cambodia. In general, Alzheimer's at age 80 is more prevalent in North America and Europe compared with other countries.


In other Alzheimer's research this summer, scientists showed that copper [3] seems to prevent the body's ability to clear the Alzheimer's-associated compound amyloid beta from the brain, leading to its accumulation. What's more, copper also seemed to play a role in the production of amyloid beta in the brain.



Earlier on HuffPost50:




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  • Make Your Meals A Rainbow


    That doesn't mean you should pour out a bag of Skittles at each meal. Try to eat foods of a variety of natural colors to gain antioxidants, said Dr. Amen.




  • Avoid These Fruits


    Just because something is a fruit, doesn't mean you should chow down on it, according to Dr. Daniel Amen, author of "Use Your Brain To Change Your Age." For brain health, Dr. Amen recommends food with a low glycemic index -- which measures how quickly food increases blood sugar -- and a lot of fiber, which benefits your intestinal tract. Certain fruit like pineapple and watermelon have high glycemic indexes and should be avoided, advises Dr. Amen. Instead, incorporate fruits like blueberries, apples, oranges, cherries, kiwi, strawberries and raspberries. When it comes to fiber, consider adding coconut to your diet. <em>Correction: In a previous version of this slide, "blood pressure" was incorrectly inserted where "blood sugar" is.</em>




  • You Need Fat


    Don't eliminate all of the fat in your diet. Instead, focus on incorporating good fats. In fact, if your cholesterol drops too low, you may be at greater risk for depression, according to Amen <a href="http://www.psychologytoday.com/blog/the-breakthrough-depression-solution/201106/low-cholesterol-and-its-psychological-effects" target="_hplink"> and several studies on low cholesterol</a>.

    So what exactly are "good fats"? Dr. Amen advises people to eat foods rich in omega-3s to promote brain health, including almonds, walnuts, brazil nuts, fish, lamb, avocados and green leafy vegetables.

    Another added benefit of eating good fats? "Your vitamins are actually absorbed better when you eat them with a little bit of fat," said Dr. Amen.




  • Choose Your Meat Wisely


    While you generally want to avoid bad fats, if you choose to eat steak, "you want to go with grass-fed, hormone-free, free-range meats" rather than grain-fed meats, said Dr. Amen. "When you feed the animals the high-glycemic foods, they actually produce less of the good fat and more of the bad fat. So they're not as good for you."

    In other words, what your food eats affects your health too, according to Dr. Amen.

    <em>Photo courtesy of <a href="http://www.flickr.com/photos/mdid/" target="_hplink">mdid</a></em>




  • Herbs And Spices Don't Just Add Flavor


    Next time you're whipping up some grub, turn to your spice rack for an extra brain boost. Spices and herbs may do more for your health than you realize. According to Dr. Amen, cinnamon balances blood sugar; garlic, oregano and rosemary increase blood flow to the brain; curry acts as an anti-inflammatory; and saffron can have anti-depressant effects.

    <em>Photo courtesy of <a href="http://www.flickr.com/photos/spence_sir/" target="_hplink">S. Diddy</a></em>




  • Pour Out That Juice


    Next time you're craving a cold glass of juice with your breakfast, think again. "Juice is sugar that is unwrapped from its fiber source, and whenever you unwrap sugar from its fiber source, it can turn toxic in your body," said Dr. Amen.

    <em>Photo courtesy of <a href="http://www.flickr.com/photos/mamchenkov/" target="_hplink">Leonid Mamchenkov</a></em>




  • What You Eat For Breakfast Matters


    You may be dreaming about that delicious breakfast muffin all night, but you should probably steer clear of the breakfast pastries. "There's way too much bad fat and sugar," said Dr. Amen. Instead, he recommends a protein-heavy breakfast like a few boiled eggs, nuts and an apple. While Dr. Amen suggests eating lean protein at each meal, he believes it is "especially important in the morning because it helps you focus," he said.

    <em>Photo courtesy of <a href="http://www.flickr.com/photos/15216811@N06/" target="_hplink">Nicola since 1972</a></em>




  • Find Supportive Friends


    The last thing you need when you're trying to eat healthy are friends who try to coerce you to be unhealthy. "You have to deal with the food pushers in your life because they'll steal your health," said Dr. Amen. "The health of the people you spend time with will often determine your longevity."

    Make sure your friends understand and support your decision to eat healthier, and try to find other people who who are on the same healthy path as you.




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