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Showing posts with label DHA. Show all posts
Showing posts with label DHA. Show all posts

Wednesday, 1 August 2018

Omega-3 fatty acids don’t protect against heart disease

Omega-3 is a type of fat. Small amounts of omega-3 fats are essential for good health and they can be found in the food that we eat.
Omega-3 fatty acids donĂ¢€™t protect against heart disease
Contrary to popular belief, taking omega-3 fatty acid supplements does not help protect you against the risk of heart disease. — AFP

The main types of omega-3 fatty acids are: alpha­linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
ALA is normally found in fats from plant foods, such as nuts and seeds (walnuts and rapeseed are rich sources).
EPA and DHA, collectively called long chain omega-3 fats, are naturally found in fatty fish, such as salmon and fish oils, including cod liver oil.
Increased consumption of omega-3 fats is widely promoted globally because of a common belief that it will protect against heart disease.
There is more than one possible mechanism for how they might help prevent heart disease, including reducing blood pressure or reducing cholesterol.
Omega-3 fats are readily available as over-the-counter supplements and they are widely bought and used.
A new Cochrane systematic review, published on July 18, 2018, in the Cochrane Library, combines the results of 79 randomised trials involving 112,059 people.
These studies assessed the effects of consuming additional omega-3 fat, compared to usual or lower omega-3 consumption, on diseases of the heart and circulation.
Twenty-five studies were assessed as highly trustworthy because they were well designed and conducted.
The studies recruited men and women – some healthy and others with existing illnesses from North America, Europe, Australia and Asia.
Participants were randomly assigned to increase their omega-3 fats or to maintain their usual intake of fat for at least a year.
Most studies investigated the impact of giving a long-chain omega-3 supplement in a capsule form and compared it to a dummy pill. Only a few assessed whole fish intake.
Most ALA trials added omega-3 fats to foods such as margarine, and gave these enriched foods, or naturally ALA-rich foods such as walnuts, to people in the intervention groups, and usual (non-enriched) foods to other participants.
The Cochrane researchers found that increasing long-chain omega-3 provides little, if any, benefit on most outcomes that they looked at.
They found high-certainty evidence that long-chain omega-3 fats had little or no meaningful effect on the risk of death from any cause.
The risk of death from any cause was 8.8% in people who had increased their intake of omega-3 fats, compared with 9% in people in the control groups.
They also found that taking more long-chain omega-3 fats (including EPA and DHA), primarily through supplements, probably makes little or no difference to risk of cardiovascular events, coronary heart deaths, coronary heart disease events, stroke or heart irregularities.
Long-chain omega-3 fats probably did reduce some blood fats, triglycerides and HDL cholesterol. Reducing triglycerides is likely to be protective of heart diseases, but reducing HDL has the opposite effect.
The researchers collected information on harms from the studies, but information on bleeding and blood clots was very limited.
The systematic review suggests that eating more ALA through food or supplements probably has little or no effect on cardiovascular deaths or deaths from any cause. However, eating more ALA probably reduces the risk of heart irregularities from 3.3% to 2.6%.
The review team found that reductions in cardiovascular events with ALA were so small that about 1,000 people would need to increase consumption of ALA for one of them to benefit. Similar results were found for cardiovascular death.
They did not find enough data from the studies to be able to measure the risk of bleeding or blood clots from using ALA.
Increasing long-chain omega-3 or ALA probably does not affect body weight or fatness.
Cochrane lead author, Dr Lee Hooper from the University of East Anglia, United Kingdom, said: “We can be confident in the findings of this review, which go against the popular belief that long-chain omega-3 supplements protect the heart.
“This large systematic review included information from many thousands of people over long periods. Despite all this information, we don’t see protective effects.
“The review provides good evidence that taking long-chain omega-3 (fish oil, EPA or DHA) supplements does not benefit heart health, or reduce our risk of stroke or death from any cause.
“The most trustworthy studies consistently showed little or no effect of long-chain omega-3 fats on cardiovascular health.
“On the other hand, while oily fish is a healthy food, it is unclear from the small number of trials whether eating more oily fish is protective of our hearts.
“This systematic review did find moderate evidence that ALA, found in plant oils (such as rapeseed or canola oil) and nuts (particularly walnuts) may be slightly protective of some diseases of the heart and circulation.
“However, the effect is very small, 143 people would need to increase their ALA intake to prevent one person developing arrhythmia. One thousand people would need to increase their ALA intake to prevent one person dying of coronary heart disease or experiencing a cardiovascular event.
“ALA is an essential fatty acid, an important part of a balanced diet, and increasing intakes may be slightly beneficial for prevention or treatment of cardiovascular disease.”
Cochrane is a global independent health research network, which produces reviews that study all of the best available evidence generated through research.
https://www.star2.com/health/2018/07/30/omega-3-fatty-acids-heart-disease/

Wednesday, 5 October 2016

The Case Against Veganism — Carefully Researched Book Spills the Beans

There's very little historical support for this eating style because no single population in the history of the world has ever survived on it. Yet it's touted to be a healthy way to eat. However, now we know it can lead to serious neurodegenerative diseases including blindness.

September 25, 2016

Story at-a-glance

  • There doesn’t appear to be a single population of any significant size in the history of the world who survived on an exclusively plant-based diet, so from a health perspective, there’s little support for the strict veganism idealized today
  • Veganism involves the complete exclusion of ALL types of animal products — not just meat and animal organs, but also products obtained from live animals, such as dairy and eggs. It also excludes seafood
  • A vegetarian diet that includes some animal foods in the form of eggs, dairy and fish, makes for a healthy balanced diet that supplies all the critical nutrients your body needs for optimal health


By Dr. Mercola
An estimated 6 million Americans are vegans, which is typically considered to be a healthy choice. However, there are drawbacks to strict veganism that need careful consideration.
Mara Kahn, author of "Vegan Betrayal: Love, Lies, and Hunger in a Plants-Only World," delves deep into the history and science of veganism, revealing many oft-ignored facts about this strictly plant-based diet.
She’s put together a compelling story, covering her personal journey from being a vegan and vegetarian to exploring diet and health and finding out the truth behind the hype. It’s really the best book I’ve ever read on this topic, as it covers the vegan issues in their entirety.
"Even though my book is titled 'Vegan Betrayal,' I do respect vegans and what they’re trying to do. My own journey led me back to vegetarianism. I know that many … vegetarians that became vegans … are suffering from diminished strength and faltering health.
I think this is a topic which has been swept under the rug and it’s not being openly discussed in the vegan community. I think it’s very important that we start this discussion. I hope this book will help kick-start that really important dialogue,” Kahn says.

Veganism Has No Historical Support for Its Health Claims

While I would never argue with anyone who decides to be a vegan for philosophical, spiritual or ethical reasons, I believe it's important to consider and address the risks if you're jumping into veganism for its purported health benefits alone.
Surveys show ethical considerations are the primary reason people convert to vegetarianism or veganism. But as Kahn reveals in her book, veganism is not the only ethical diet. She also presents compelling arguments that it's not a historically validated diet.
Kahn became a vegetarian at age 19, while traveling in Europe. She became an overnight convert after meeting a young vegan woman who Kahn refers to as “a beautiful specimen of humanity” and “extremely healthy” — not realizing this same woman would return to eating meat just five years later due to fading energy.
Up to that time, Kahn had eaten a very meat-based American-style diet, including bacon and hamburgers. At that time, in the 1970s, veganism was largely unheard of. It didn't get a strong hold in the U.S. until the 1980s.
Interestingly enough, Kahn’s investigation reveals there doesn’t appear to be a single cultural group in the history of the world who actually survived long-term on an exclusively plant-based diet. So from a health perspective, there’s very little historical support for the strict veganism idealized today.
"I did a thorough research of the history of vegetarianism. In fact, I spent almost six years researching this book. I'm a journalist … I love to dig deep," Kahn says.
"At this point, it's really important that we distinguish between vegetarianism and veganism. Vegetarianism has a very long and honorable history. It goes back at least 2,500 years to Greece, and much further than that in the Indus Valley, India and that part of the world.
It has proven itself to be a viable diet … [Yet even] in the Northern parts of India, the Kashmir regions, they eat meat because the climate is so different in the mountainous regions of North India.
Vegetarianism has a very long and noble history with verified health results. However, veganism … is a non-historical diet … Its health benefits are not verified.
There were scattered enclaves of religious people that lived cloistered lives whoprobably did follow a vegan diet … but these were very, very tiny populations, and we have no idea if they were healthy and how long they lived.”

There Are Short-Term Benefits to Veganism, but Long-Term Risks

From a historical perspective, veganism is a very recent development. The roots of veganism go back to England, when in 1944, Donald Watson coined the term “vegan.” Watson’s primary argument for veganism was one of ethics. At the age of 14, he’d witnessed the slaughter of a pig, which left him horrified.
Immediately, he decided to stop eating meat and wanted the whole world to follow suit, despite having no training in nutrition. Veganism is based on ideology, not human physiology, Kahn reminds us in her book, which also delves into human evolution.
Part of the confusion is that many vegans appear quite healthy in the earlier stages. This isn't so surprising when you consider the fact that many switch from processed foods to a mostly raw plant-based diet. The influx of live foods will undoubtedly improve your health.
However, in the long term, the absence of all animal-based foods can take a toll, as certain nutrients cannot be obtained from the plant kingdom. Carnosine, carnitine, taurine, retinol, vitamin D3, conjugated linoleic acid and long-chained omega-3 fats are examples. B12 deficiency is also very common among vegans.
After six or seven years, the B12 stored in your liver will be completely exhausted, at which point you may start to experience serious neurodegenerative diseases. There are many documented cases of blindness from B12 deficiency, as well as other neurological disorders.

Historically, Vegetarianism Always Included Some Animal Foods

Vegetarianism typically allows both dairy and eggs. Back in Pythagoras’ days, early Western vegetarians also ate fish. (Today, this “branch” of vegetarianism is sometimes separated out and referred to as pescetarianism.)
My passion has been identifying food to optimize health and I'm absolutely convinced that seafood is one of the healthiest foods on the planet, primarily because of its docosahexaenoic acid (DHA) content — a 22-carbon omega-3 fat that is absolutely essential for your health, as it's a structural component of your cell membranes.
If you have low DHA levels, it's almost physiologically impossible to be healthy because it's such an important part of energy generation at the molecular level. You need DHA, which is only found in fatty fish and certain other marine animals like krill.
There's even quantum physics going on with respect to its ability to capture light and integrate it into your system. For example, DHA in your retinal pigmented epithelium is responsible for converting sunlight into vital DC electric current your body needs. If you're deficient, your ability to generate energy by your mitochondria will be impaired.
Granted, water pollution is a major concern today, so you have to eat really low on the food chain. Anchovies, sardines, herring, wild Alaskan salmon, fish roe and krill are all good choices as they're high in omega-3s while being low in mercury and other pollutants.

Like It or Not, You Need Marine-Based DHA

If you exclude these foods, you're just not going to be healthy. And contrary to popular belief, you simply cannot obtain all the DHA you need from plant sources. Plant-based omega-3 (alpha-linolenic acid or ALA) has 18 carbons whereas marine-based omega-3s (DHA and eicosapentaenoic acid or EPA) have 22 and 20 respectively. The difference in the length of the carbon chain makes a significant difference in terms of functionality.
ALA functions as a source of fuel (food), whereas EPA and DHA are structural elements. More than 90 percent of the omega-3 fat found in your brain tissue is DHA, which suggests how important it is for healthy neurological function, for example.
The problem is that, although your body can convert some of the ALA found in plants to the DHA found in marine oils, it is very rare for it to be more than 5 percent — the typical conversion rate is 1 to 3 percent, or even less.1 This simply isn't enough to have any significant benefit.
So please, don't make the mistake of thinking you can forgo marine-sourced DHA for a plant-based ALA found in flaxseed, flaxseed oil, chia seeds, walnuts and leafy greens.

Adding Fish Can Make a Big Difference

I think one of the reasons why vegetarians — at least those who follow Pythagoras' model, which includes fish — seem so healthy is because this diet is lower in protein than the conventional meat-based diet. When you eat excessive protein, you stimulate powerful biochemical pathways that trigger disease. This, combined with the fact that fish provides critical omega-3 and other healthy fats and cofactors, makes a strong case for the "pescetarian" form of vegetarianism.
“I agree totally,” Kahn says. “I remember trying to be an omnivore again … I started eating plenty of fish and my health skyrocketed almost immediately … My energy just skyrocketed. I started sleeping better. My nerves became calm. I was in intense gratitude to this first [wild salmon] that I ate; for the energy and the renewed love for life that it bestowed on me. It was absolutely amazing.
I did interviews and talked to or heard the stories of hundreds of vegans and ex-vegans, and almost invariably … the same thing happened to them … I think there's a very good reason Pythagoras ate some fish from time to time. It was plentiful in the Mediterranean region where he lived. It wasn't contaminated. There's reason he prescribed it to his everyday followers in the towns. That reason is probably DHA …
DHA is really a problem with vegans … In fact, two of the founders of veganism, as they became older, suffered from Parkinson’s disease. They had their DHA tested and it was zero … I eat sardines every other day. The rush of powerful and sustained energy I get from them I cannot find anywhere in the plant world.”

Low Protein and Low Fat — 2 Common Health Barriers for Vegans

While keeping your protein low is a wise move, excessively low protein can become a problem for vegans — especially if your diet is also low in healthy fats. Some will get just 8 to 12 percent protein from plants in their daily diet, which can trigger muscle wasting. "In that sense, vegans are consuming flesh after all — their own — if they're not eating enough protein," Kahn says.
Low fat is another, and in my view, more concerning problem, among vegans. When you eat a high-net carb diet (total carbs minus fiber), you're essentially burning carbohydrates as your primary fuel. If you shift down to relatively low levels of net carbs, which is easy to do on a vegetarian diet since vegetables are so high in fiber, then your body starts burning fat as its primary fuel. This means you need to increase the amount of healthy fats in your diet in order to satisfy your body's fuel demands.
Sufficient dietary fat is also essential for maintaining healthy hormone levels, Kahn notes, including your sex hormones. Raw veganism in particular is associated with loss of menses (amenorrhea), due to low calorie and fat intake, increasing your risk for infertility and osteoporosis.
Low fat is likely far more troublesome than low protein, because once you start burning fat for fuel, powerful protein-sparing processes start taking place, allowing you to get by with as little as 6 to 8 percent protein without risking muscle wasting. I only have 8 percent protein in my diet and I do not believe I'm protein deficient. That's because fat is my primary fuel. If I were burning carbs, I would not fare well at all with such a low amount of protein.

Veganism Has a High Drop Out Rate

The health problems associated with veganism create a high dropout rate. It's difficult to find good statistics on this, as people don't want to discuss it. Many are ashamed, feeling they've somehow "failed," and many are shamed by their fellow vegans, who believe they're making a huge mistake to go back to eating animal foods.
"I've even read accounts of ex-vegans who describe it as kind of cult-ish. The shaming that ensues is very powerful … One vegan told me that when she decided to go and buy some eggs for the first time in, I don't know, 10 or 15 years … her boyfriend, who was a staunch vegan, refused to go in with her. In fact, he had told her … he would rather she was a continually suffering vegan than to be a healthy meat-eater.
This, to me, was a perfect illustration of what I personally call Reverse Speciesism, preferring the health of an animal over the health of your fellow human being, which is really kind of a new thing, I think, in human history. It's not talked about much in the vegan community — the high dropout rate — but the numbers are large … It's estimated about 50 percent of vegans have left because of declining strength and declining health."

Even Vegan Diet Affects Animals

What many vegans fail to integrate into their overall evaluation is that even the consumption of an exclusively plant-based diet involves killing a wide variety of animals. Not intentionally, of course, but rather as an artifact of the process of growing the food. Essentially, there's no animal-free lunch, which is a direct quote from Kahn's book. There's going to be some type of destruction of life involved. Then there's the issue of plant consciousness as well.
As noted by Kahn, unless you're growing all your food by yourself in a no-till organic setting using hand tools, animals are destroyed in industrial agriculture. Studies by reputable scientists show up to 70 percent of rodents and small animals present in industrial growing fields end up being killed by the machinery. Animals are also killed in traps, and during food storage and transportation. As Kahn says:
"To be a vegan, you have to somewhere draw the line on what food you will eat and what you won't. For most of them, it's a matter of consciousness. Is the living thing conscious of what's going on? Is it suffering? That demarcation between an animal that's conscious and unconscious has totally changed throughout history and throughout cultures.
For instance, now they're looking at fish. In the past, it was just decided, because they were so cold looking and expressionless, that fish didn't have consciousness. But new testing is showing that perhaps they do; perhaps they can feel pain … People are taking that further and looking at insects. I interviewed scientists that work with insects. Some of them really do believe that insects have consciousness and an intelligence that we can't even understand …
The same with plants … Brilliant botanists believe that plants have elevated intelligence that we can't even begin to understand, because we don't speak the same 'language.' They know for sure that plants absolutely know when they are being eaten.
Living plants send out chemicals to warn their neighbors of danger ahead and they send out chemicals that summon insect bodyguards to ward off predators. These are intelligent beings that want to live. They have what I call 'want to live, don't want to die' skills that are very developed."
It's also worth noting that some of the research vegans rely on to substantiate their dietary choices as healthy actually do not offer such proof. For example, when Kahn dug deep into some of the most well-known studies that vegans love to cite, she discovered they actually define vegetarianism in a very broad way. They do not support a purely plant-based (vegan) diet at all. Not only did these studies include fish-eaters, but also dairy-eaters and even those who ate red meat once a week.

Why the American Dietetic Association Now Promotes Plant-Based Diet

Kahn says to be very wary of vegan studies conducted by vegans. As with all conflicts of interest, people have a tendency to find what they want to find, even if they have to massage the data a bit to get there. Interestingly, in recent years the Academy of Nutrition and Dietetics (AND), formerly the American Dietetic Association (ADA), made the transition to promoting a plant-based diet. As it turns out, this decision was primarily based on the recommendations of a devoted vegan and a vegetarian.
“The ADA position paper, which came out in 2009, recommends a vegetarian and a vegan diet to all people of all ages, from infancy to old age. If you do some more digging, as journalists love to do, [you find] it was co-authored by two people. One was a vegetarian and one was a vegan. In fact, the vegetarian belongs to a religious denomination that encourages the spreading of vegetarianism across the world.
My question is: why weren’t these two authors tagged for conflict of interest? They’re recommending this to the whole world and to all ages …
There are some serious flaws in their research. First of all, I looked at their sources. I can't remember if it was 100 or 200 sources. I could find only 17 in all those sources that were exclusive to vegans. You cannot take vegetarian research and apply it to vegans. It just doesn't work. There are too many missing nutrients in a vegan diet that are present in a vegetarian diet.
I wish that vegans would not just read vegan blogs and websites and recommendations from other vegans. They need to look at science, at research — non-biased sources. They need to read my book, which would tell them everything they want to know about the history, philosophy and nutritional facts of veganism.”
That's not an inflated claim, I can assure you. I've read hundreds of health books, and Kahn's book, "Vegan Betrayal," is among the very best when it comes to teasing out the truth about veganism and health.

Balance Ethics and Health When Choosing Your Diet

I'm not opposed to vegetarianism. By Pythagoras' definition, I am a vegetarian. I eat very small amounts of animal protein; mostly fish. Occasionally, I'll have some organic grass-fed meat or free-range pastured chicken. But meats are not a cornerstone staple in my diet, and I believe most people could benefit from lowering their meat consumption. It shouldn't be entirely excluded, however, because animal foods do contain very valuable nutrients your body needs for optimal health.
Organic pastured eggs are another source of incredibly healthy nutrients. Ditto for raw butter. If ethics and animal welfare are your concerns, I would encourage you to investigate and educate yourself on humanely-raised animal foods.
Yes, the animal will die in the end, but there's a tremendous difference between the life of an animal raised in a concentrated animal feeding operation (CAFO) and one raised on pasture that is allowed to live a full, healthy and stress-free life. There's also a big difference in the way they're slaughtered.
At the end of the day, you have to choose between the life of an animal somewhere — even if only a few rodents caught in a harvester — or your own health. A balance must be struck between optimizing your health and causing the least amount of unnecessary suffering.
“If you look at the most lauded diet in the world, the Mediterranean diet — which by the way, they were doing a long-term study on, and which they ended early in 2013 because the benefits were so enormous they felt it was unethical to deprive the control group — the Mediterranean diet, which is mostly plants, limited fish, limited red meat, limited dairy, [gives you] all the carni-nutrients you need … It’s a complete diet.
It's been named one of the best diets in the world. It's historically validated for thousands of years and many, many generations that this diet confers long lasting health and long life … The vegan diet is not validated. That's what we need to work on — getting those research studies done, so that future vegans will know what they're up against," Kahn says.

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http://articles.mercola.com/sites/articles/archive/2016/09/25/veganism.aspx

Monday, 3 October 2016

Obesity Accelerates Brain Aging

The number on the scale reveals far more than just your weight. If you're overweight or obese, the damage extends past your waistline. Simple lifestyle strategies can help, from the inside out.

September 01, 2016

weight management

Story at-a-glance

  • Obesity has been linked to accelerated loss of white brain matter — brain tissue that allows for communication between the different parts of your brain
  • Overweight 50-year-olds had comparable white matter volume to that of slim 60-year-olds, suggesting excess weight can age your brain by about 10 years once you pass middle-age
  • Simple lifestyle strategies can help optimize your brain health AND help you lose weight. This includes exercise, calorie restriction or intermittent fasting, reducing net carbs and increasing healthy fats
By Dr. Mercola
It's become a well-known fact that excess sugar harms your health by setting up the conditions for obesity and diabetes. Research1 has also shown a steady diet high in high-fructose corn syrup (HFCS) can significantly impair your cognitive abilities by producing a decline in synaptic activity.
In one animal study, rats fed fructose syrup for six weeks showed signs of cognitive impairment, as they struggled to find their way out of a maze. Their brain cells had trouble signaling each other, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier.
The fructose-fed rats also showed signs of resistance to insulin, a hormone that — in addition to controlling your blood sugar — also controls synaptic function in your brain.
Because insulin is able to pass through your blood-brain barrier, it can trigger neurological processes that are important for learning and memory. Consuming large amounts of fructose may block insulin's ability to regulate how your brain cells store and use sugar for the energy needed to fuel thoughts and emotions.
Considering the fact that HFCS, which is so prevalent in processed foods, is a major risk factor for obesity, it's not such a stretch to imagine that obesity may be linked to declining brain health as well. In fact, this is precisely what studies show.

Obesity Speeds Up Brain Aging

Most recently, a study published in the journal Neurobiology of Aging found structural changes in the brains of overweight people — changes typically seen in far older individuals. As reported in the Borneo Post:2
"After scanning brains of 473 people aged between 20 and 87 and dividing them into lean and overweight categories, scientists discovered that extra weight would accelerate the loss of the brain's white matter …
Scientists then calculated how much that white matter volume related to age across the two groups. They found that an overweight 50-year-old had a comparable white matter volume to a slim 60-year-old person.
'The overall message is that brains basically appear to be 10 years older if you are overweight or obese,' said Lisa Ronan, lead author of the study from Cambridge University."
Your white brain matter allows for communication between the different parts of your brain, and previous investigations have shown that this tissue tends to decrease with age. Loss of white brain matter has also been linked to cognitive decline, and it's a recognized risk factor for dementia.

Fat Cells May Promote Inflammation That Speeds Brain Aging

Interestingly, while overweight individuals showed more rapid loss of white brain matter, and other studies have linked obesity to an increased risk of Alzheimer's disease, no discernible differences in thinking skills were observed in this study. This surprising finding has yet to be explained.
The exact reason why excess body weight promotes loss of white brain matter is also undetermined. WebMD quotes Mike Henne, Ph.D., a spokesman for the American Federation for Aging Research, who says:3
"One possibility, and the researchers talk about that [in the report], is that when you are obese your fat cells are producing more inflammatory agents and your white matter is more sensitive to it. That is a leading theory in the field."

Mediterranean Diet Boosts Cognition

In related news, a review of 135 studies recently concluded that a Mediterranean-style diet benefits cognition and reduces your chances of developing Alzheimer's. As reported by Medical News Today:4
"In relation to memory, participants who closely followed the Mediterranean diet experienced improvements in long-term and working memory, as well as improvements in delayed recognition, executive memory and visual constructs.
Greater adherence to the Mediterranean diet was also associated with improvements in attention and language …"
While there are many variations, this type of diet is typically high in plant-based foods and healthy fats such as raw nuts and olive oil, while fish and poultry are emphasized over red meat.
Perhaps most importantly, the Mediterranean diet focuses on real food, downplaying processed foods that are invariably loaded with health-harming sugars and processed, damaged fats like vegetable oils.
The present study did not try to determine exactly WHY the Mediterranean diet boosts brain health, but this type of diet has already been shown to produce a number of beneficial health effects that can help answer this question. For example, the Mediterranean diet has been shown to:
Reduce inflammation
Improve weight management and reduce risk of obesity
Increase micronutrient intake
Improve antioxidant intake
Improve vitamin and mineral balances
Improve cellular energy metabolism
Improve lipid profiles
Beneficially alter gut microbiome

Your Brain Requires Healthy Fats for Optimal Functioning

Answers were also gleaned from a 2015 study,5 which found that seniors with risk factors for cardiovascular disease who followed a low-fat diet experienced a significant decrease in memory and cognition compared to those who ate a Mediterranean diet high in either olive oil or nuts.
Those who fared the best, in terms of memory, were those who ate a Mediterranean diet supplemented with 30 grams of nuts each day. They had the most significant improvements in memory.
Meanwhile, those who ate a Mediterranean diet supplemented with 1 liter of extra virgin olive oil each week had the most significant improvements in cognitive function. Both nuts and olive oil are healthy natural, unprocessed fats your body needs, so it's not surprising to find higher amounts of healthy fats improved brain function.
Previous research from the Mayo Clinic has also shown that high-fat diets are associated with a 42 percent reduced risk of mild cognitive impairment (a precursor to Alzheimer's), while diets rich in carbohydrates raise your risk by 89 percent! As reported by USA Today in 2012:6
"Several popular diets, including the Mediterranean (fish, poultry-based protein and plenty of plant-based foods and healthy fats) … make pitches for the multiple health benefits derived from lowering carbohydrate intake, including reduced risk for heart disease, diabetes and improved brain health."
Keep in mind that while limiting net carbs (total carbohydrates minus fiber) is one important aspect, increasing healthy fats is part and parcel of the whole equation.
Not only do you need healthy fats for optimal brain function, you also need it for energy, hormone production and an array of other biological functions, including optimal mitochondrial function and, believe it or not, weight management.

DHA — An Important Brain Health Component

Perhaps the most important fat for your brain is the animal-based omega-3 fat docosahexaenoic acid (DHA), found in certain seafood. Good choices include fatty cold-water fish such as wild-caught Alaskan sockeye salmon, sardines, anchovies and herring. Fish roe and krill oil are other good sources.
The importance of animal-based omega-3 fats (especially DHA) for brain health has been demonstrated in many studies.
For example, studies have shown it can help prevent Alzheimer's,7 improve attention-deficit/hyperactivity disorder (ADHD) symptoms and depression and delay progression to psychosis among patients at high risk for schizophrenia.
Going back to the rat study mentioned earlier, rats given DHA in conjunction with their high fructose diet were able to navigate the maze better and faster than the rats in the non-DHA group, suggesting the DHA is protective against the harmful effects of fructose.
DHA is essential for synaptic function — it helps your brain cells transmit signals to one another, which is the mechanism that makes learning and memory possible. And since your body cannot produce DHA, you must get it from your diet.
Importantly, DHA is a structural element of every cell in your body and plays a role in the communication within the cell and between cells. As such, DHA is not just another food (fuel). The fact that it is a structural element of your cells help explain why omega-3 deficiency is so detrimental to your health.
And since more than 90 percent of the omega-3 fat found in brain tissue is DHA, it's particularly important for brain health. DHA and eicosapentaenoic acid (EPA) also have a profoundly important influence on your mitochondrial function.
DHA in your cell membranes actually helps convert the photons from sunlight into DC electric current, which in turns fuels your mitochondria and energy production. I am convinced that having enough DHA in your cell membranes is one of the most important health strategies available. And remember, your body simply cannot convert plant-based omega-3 to DHA in any quantity that is therapeutically useful.

Other Studies Linking Obesity With Declines in Cognition

The idea that your weight may be a risk factor for Alzheimer's has been brought forth by a number of studies. Obese adults often have additional risk factors for Alzheimer's, including high blood pressure and diabetes. Obesity is also linked to chronic inflammation, which might make Alzheimer's worse, along with insulin resistance, another known risk factor for Alzheimer's.
  • In 2008, research revealed that central obesity (excess weight around your midsection) is linked with an increased risk of dementia.8
  • Research published in 2011 found a strong correlation between body mass index (BMI) and high levels of beta-amyloid, the protein that tends to accumulate in the brains of Alzheimer's patients, causing plaque buildup. It is believed that beta-amyloid destroys nerve cells, contributing to the cognitive and behavioral problems typical of the disease.9
  • A 14-year-long study published in July 2016, found that among people who developed Alzheimer's disease, those who were overweight or obese at the age of 50 developed symptoms nearly seven months' sooner than those of a healthy mid-life weight. Further, the onset of symptoms moved up by 6.7 months for each unit increase in midlife BMI. Those with a high BMI were also more likely to have greater amounts of amyloid proteins in their brain.10

Three Keys for Weight Loss and Brain Health

On the bright side, a number of simple lifestyle strategies can help optimize your brain health and ward off age-related decline. This includes the following, which just so happen to be identical to those for weight loss:
  • Exercise, especially high-intensity interval training.
  • Calorie restriction (intermittent fasting appears to have many of the same benefits while being easier to comply with).
  • Reducing net carbs (especially grains and sugars) and increasing high-quality healthy fats (such as olive oil, coconut oil, MC oil, butter from raw grass-fed organic milk, raw nuts, organic pastured egg yolks and avocados). According to neurologist Dr. David Perlmutter, author of the book, "Grain Brain," a low-carb diet high in healthy fats is a key component of Alzheimer's prevention.

Other Strategies That Help Protect Your Brain

You also need plenty of high-quality omega-3 fats, especially DHA. I prefer krill oil to fish oil, as krill oil also contains astaxanthin, which is particularly beneficial for your brain. Astaxanthin is a carotenoid that's very good for reducing free radical-mediated damage to fat, and as mentioned, the majority of your brain — 60 or 70 percent — is fat; mostly DHA. Two other nutrients that play important roles in your brain health are:
  • Vitamin D: Researchers have located metabolic pathways for vitamin D in the brain's hippocampus and cerebellum; areas that are involved in planning, information processing and memory formation. In older adults, research has shown that low vitamin D levels are associated with poorer brain function.
  • Choline: Choline reduces inflammation and plays a role in nerve communication. Eggs and meat are two of the best dietary sources of choline. If you do not consume animal foods, you may be at risk of a deficiency and want to consider supplementation.
The state of your gastrointestinal (GI) tract is another important consideration that can have a significant influence on your brain function. Your gut is quite literally your "second brain." Just as you have neurons in your brain, you also have neurons in your gut, and gut bacteria transmit information from your GI tract to your brain via your vagus nerve.
Abnormal gut flora has been associated with abnormal brain development, and may be an overlooked culprit in many cases of depression. In addition to avoiding sugar, one of the best ways to support gut health is to consume fermented vegetables, which are loaded with beneficial bacteria.
Last but not least, it is crucial to fully appreciate the importance of sleep. The latest sleep guidelines, based on 300 studies looking at the health effects of sleep, confirm that most adults need right around eight hours of sleep for optimal health.
It's particularly important for brain health, because the ONLY time your brain can detoxify is during deep sleep, which is why poor sleepers are more prone to developing neurological disorders such as Alzheimer's. So truly, if you want your brain to function optimally, be sure to address any sleep problems you may have.
http://articles.mercola.com/sites/articles/archive/2016/09/01/brain-aging.aspx