For most people, the single most important step to avoiding neurodegeneration & improving brain function is optimizing their diet. Neuroscientists broadly agree that the Standard American Diet (aptly dubbed ‘SAD’) has been a key contributor to the surge in brain disorders in the US over the past several decades. But the brain has a powerful capacity to heal itself when insults are taken away and the right nutrients are added - this is why functional medicine doctors are seeing more and more people actually begin to reverse their dementia and Parkinson’s through nutrition and lifestyle changes.
Repeated studies have found that people who follow a classic Mediterranean style of eating, focused on fresh, fibrous vegetables, fruit, fatty fish, and healthy nuts, seeds & oils such as extra virgin olive oil have a reduced risk of dementia and longer healthspans generally than the overall population. These people avoid processed foods, sugar and industrial grain & seed oils, such as canola and soybean oil.
To optimize your brain health, cut out or minimize:
Sugar and refined, processed carbohydrates. If you have healthy blood sugar, your entire blood volume at any given moment carries about 1 teaspoon of sugar. When we consume a blueberry muffin or soda, we are essentially funneling 6-8 teaspoons of additional sugar into that system. Your body likes homeostasis and tries continually to keep your blood sugar in the 1 teaspoon zone, releasing insulin from the pancreas when sugar is consumed so that glucose can enter the cells of your liver, muscle and fat tissue. However, the pancreas is not an instrument of precision – when we consume a sugary, high carbohydrate meal, it often over responds, sending your blood sugar to the floor and giving you the familiar symptoms of ‘hanger’. This not only keeps you locked into the roller coaster of reaching for sugary, starchy foods that drive weight gain and inflammation, but by keeping insulin levels chronically high during the day, we set the stage for diabetes and dementia. A stunning 40% of Alzheimer's cases may be ultimately owed to chronically elevated insulin, as reported by the Journal of Alzheimer's Disease.
In fact, neuroscientists are now calling Alzheimer’s ‘Type III Diabetes.’ We need a certain amount of glucose to fuel our brain, but too much is damaging - the human body was designed to lower blood sugar on only an occasional basis, not an hourly basis. Modern diets high in sweets, sodas, pastries, bread, pasta, corn, grains and other starchy foods produce a series of shocks to the body day in and day out, ultimately making neurons insulin-resistant and leaving too much sugar and insulin circulating in the brain, which causes inflammation and speeds cell death. While we have an incredible innate ability to repair against inflammation, our repair mechanisms work best when we're in a low insulin state.
A Mayo Clinic study assessing fat, protein and carbohydrate intake found that people with the highest carb intake were 3.6 times likelier to develop cognitive impairment than those who favored fats and proteins as a calorie source. A New England Journal of Medicine study of over 2,000 individuals looking solely at blood sugar found an almost perfect correlation between higher levels of blood sugar and the development of dementia – and the levels of blood sugar in question were far below the range typically used to characterize diabetes.
In addition to wreaking havoc on your insulin metabolism, sugar is itself a potent brain neurotoxin that has been linked to depression, anxiety, ADD, and dementia. The typical American adult consumes 150 pounds of added sugar a year, including fake sugars like aspartame, saccharine and sucralose, and high-fructose corn syrup, much of it from processed foods. Sugars feed yeast, fungi & bad bacteria in the gut, and reduce your levels of BDNF (Brain-Derived Neurotrophic Factor), a hormone that triggers the growth of new neurons and stem cells in the brain, repairing crucial brain structures.
Detoxifying from sugar requires eliminating not just obvious sugary foods but also processed grains, which turn into glucose instantly, spiking your blood sugar. Focus on fruits and vegetables with a low glycemic index that promote steady absorption of glucose. (The glycemic-load system ranks foods in terms of how quickly they raise your blood sugar levels, in relationship to the amount of fiber a food contains - the more fiber, the lower the food’s effects on insulin.) Excellent sources of lower glycemic carbohydrates include artichokes, asparagus, broccoli, brussel sprouts, greens, leeks, onions, peppers, squash, zucchini, tomatoes, turnips, rutabaga and cabbage.
If you have a sweet tooth, learn to love organic dark chocolate without added sugar. Chocolate with cocoa content of 80% percent or higher (the higher, the better) is rich in theobromine, a powerful antioxidant that helps slow cellular aging and reduces the risk of heart disease.
Gluten. Modern gluten is essentially immune reactive – in other words, eating it creates an immune response against your own nervous system, an effect that researchers increasingly believe may occur in everyone, not just gluten-sensitive individuals and people with celiac. The basic understanding for years was that the destruction caused by gluten was limited to the intestinal tract, but numerous studies have now confirmed that gluten is a major contributor to inflammation and degeneration of the brain & nervous system, with one study of patients manifesting gluten sensitivity in the brain finding that only a third of them also suffered from GI disorders.
Industrialized oils and transfats. Refined vegetable and seed oils such as soybean, corn and canola oil are some of the most noxious ingredients in the food supply. These oils are predominantly composed of omega-6 fats, which are essential for life but drive inflammation when overconsumed. Unfortunately, they are often hidden in very inconspicuous places that may even be marketed as healthy, such as salad dressings, granola bars and dried fruit. One common pitfall is roasted nuts, which are typically fried in these refined oils (look for nuts labeled ‘dry roasted’).
It’s worth noting that nature doesn't create bad fats - we humans have. Making any of these oils requires industrial processing that damages the original food, but arguably the most problematic step is a process called deodorization, which makes the oils bland and odorless. Manufacturers love this because it allows them to use the oils in all parts of the food supply, which in itself raises common sense alarm bells – the reason these oils work interchangeably in pasta dishes, chicken fryers, energy bars, and much more is because they have been processed to the point of having no taste.
Deodorization creates transfat, man-made fats associated with an increased risk of early death and worse memory function, even in people that are young and healthy. Processed vegetable and seed oils contain up to 5% transfat, and it takes very little transfat in the diet to develop cognitive impairment. Across several studies, people who consumed two grams a day of trans fats had twice the risk of those who ate less than two grams. Furthermore, most people in those studies ate at least two grams a day, with the majority of participants eating more than double that on a regular basis.
Typical processed foods that are high in trans fats include baked goods, like commercial doughnuts, cakes, piecrusts, biscuits, and frozen pizza; many snack foods, such as cookies and crackers; margarines (stick or spread); and commercial cheeses, along with many other spreadable or creamy products. The more packaged and processed foods you consume, the more hidden trans fats and artificial substances you may be consuming, and the higher your risk of negative outcomes.
Factory farmed meats that contain antibiotics and hormones. Look for grass fed and pastured meats from a local farm (second best is organic).
Chemical preservatives and additives. Build your diet around organic, whole foods and if you must have packaged foods, avoid chemical preservatives and additives such as carrageenan (often found in nut milks) and nitrites/nitrates (in bacon, sandwich meats, salami and sausages).
Conversely, the following foods are neuroprotective and supply critical nutrients for your brain:
Omega-3 fats. When our bodies are burning the right fats, we enhance the activity of gene pathways that help us produce protective antioxidants and decrease the activity of pathways that promote inflammation. This directly impacts the health of our brain tissue and our cognitive function - research shows that people whose diets have less than four grams of omega 3’s a day have the highest rates of brain shrinkage over time and the highest risk of Alzheimer’s. Those whose diets have six grams or more have the healthiest, most “youthful” brains. Luckily, it doesn’t take much to reach our brain-fat goals. A small piece of Alaskan salmon (just three ounces) provides about two grams of omega-3’s. Avocados, spirulina, walnuts and chia seeds are also good sources of omega-3 fats.