The human brain is an incredibly sophisticated organ. It has around 100 billion neurons that send nerve impulses at speeds of around 250 miles per hour. But like any other part of the human body, the brain needs essential raw materials to function properly. Composed of about 73 percent water and weighing about three pounds, the brain is just two percent of the average person’s body weight but uses 20 percent of our calorie intake. Keeping our brains fueled and healthy is crucial.

WHOLE GRAINS

The brain needs energy to work, and its main source of energy is glucose. This simple sugar, found in many foods, is carried in the bloodstream and converted into energy by tissue cells throughout the body. Unlike the rest of the body, however, the brain cannot store this energy, so it needs a constant and steady supply of glucose. Whole grains are complex carbohydrates, which means they release their glucose into the bloodstream slowly, helping us stay alert and focused through the day. Whole grains are also rich in B vitamins that perform a number of beneficial functions for the brain.

B VITAMINS

Collectively, the eight water-soluble organic compounds known as B vitamins take important steps to keep our brains healthy. B6, B12, and B9 reduce the levels of homocysteine, an amino acid that can damage the lining of the arteries and may increase risk of heart attack or stroke. B1, B2, and B5 all play a critical role in the metabolic processes that turn food into energy to power the brain, while B12 also promotes the development of red blood cells that carry oxygen to the brain. A number of B vitamins, including folic acid, are vital for producing the neurotransmitters that relay signals between neurons, a reduction of which can affect our cognitive ability, causing fatigue, depression, anxiety, aches, and pains.

BERRIES

Our brains begin to lose some cognitive function before we turn 30, but berries, especially dark berries like blackberries, blueberries, and cherries, can potentially slow this natural aging process. The problem is oxidative stress, where the body becomes increasingly inefficient at removing the harmful by-product of metabolism called free radicals. These destabilize our body's cells by stealing electrons from cells in the brain and elsewhere, causing considerable damage. Berries are packed with antioxidant molecules called flavonoids that protect cells from damage by sacrificing their own electrons to free radicals. This could delay the onset of Alzheimer’s disease and dementia.

OILY FISH

Oily fish contain many nutrients needed by the brain, including omega-3 fatty acids. The body can’t produce omega-3, so it’s likely that eating foods packed with omega-3 will benefit the brain over time. Fish such as salmon and sardines contain two of the main omega-3s, known as EPA and DHA. These are involved in many brain processes, including gene expression reducing oxidative stress, helping blood flow around the brain, producing new neurons, and maintaining the level of neurotransmitters. Some studies suggest that an omega-3 rich diet could significantly reduce the risk of dementia and Alzheimer’s disease.

BROCCOLI (AND LEAFY GREENS)

Cruciferous vegetables like broccoli are also important for enhancing your cognitive function. Research suggests that this could be because broccoli is rich in a sulfur-containing compound called glucosinolate that slows the breakdown of acetylcholine, an important neurotransmitter. Acetylcholine is needed by the central nervous system and plays a significant role in memory and learning—studies show that people suffering from Alzheimer’s disease have abnormally low levels of acetylcholine. A recent report suggests that a daily serving of leafy greens, such as spinach, or broccoli, could keep our brains around 11 years younger.

WATER

Although water isn’t usually considered a food, it is absolutely crucial to brain health. Water is a major source of nutrients for our thirsty brains, is essential for removing toxins, and provides cushioning and lubrication for brain tissues. Every chemical reaction in the brain requires water, especially energy production, so dehydration quickly impairs brain function. Even a small reduction in hydration can cause confusion, fatigue, and dizziness. And it is real water we need, not tea, coffee, soda, or even purified or fizzy water. All of those have been stripped of the precious nutrients and natural electrolytes that water has and the brain needs.

We asked some big questions about living a better life. Discover more about how we can overcome the world’s biggest challenges at natgeo.com/questionsforabetterlife