A Harvard brain expert eats these 10 grocery foods to stay 'sharp and focused'—at any age - CNBC

I never go grocery shopping when I'm hungry. People who do are more tempted to buy unhealthy comfort snacks and packaged goods, rather than whole, nutritious and satisfying options.

I'm very intentional about what I put in my body. So as a nutritional psychiatrist and author of "This Is Your Brain on Food," people often ask me what they should always stock their kitchen with to keep their brains sharp and focused — at any age.

To make my grocery list easy to remember, I created the acronym BRAIN FOODS:

• B: Berries and beans
• R: Rainbow colors of fruits and vegetables
• A: Antioxidants
• I: Include lean proteins and plant-based proteins
• N: Nuts
• F: Fiber-rich foods and fermented foods
• O: Oils
• O: Omega-rich foods
• D: Dairy
• S: Spices

1. Berries and beans

Blueberries, blackberries, raspberries and strawberries are all excellent berry choices.

Make sure to eat ripe berries soon, since they don't last long (even in the fridge). At times of the year when fresh, ripe berries aren't available, frozen berries are fine as long as they don't have added sugar or other additives.

Beans, legumes and lentils are also healthy and inexpensive sources of nutrients and vitamins. They're also easy to prepare and can be a side dish or an appetizer.

2. Rainbow colors for fruits and vegetables

From red cabbage to radicchio to green and yellow bell peppers, buying vibrantly colored veggies will help expand your palate and maximize the range of nutrients that are beneficial to your brain. 

The same applies to fruits. Apples, pineapples, kiwis and citrus all come in a wide variety of colors. Just be careful not to overdo it with sweet fruits like grapes and mangoes.

The most important color of all is green. My favorites are arugula, romaine, Bibb lettuce, endive and bok choy.

3. Antioxidants

Dark chocolate is a great source of antioxidants, as long as you stick to the extra dark stuff that doesn't have added sugar.

Many vitamins are crucial antioxidants, and you can get them from a broad range of dietary sources. If you're considering taking any sort of multivitamin supplement, I recommend checking with your doctor first.

4. Include lean proteins and plant-based proteins

Well-sourced lean poultry, seafood, pastured eggs and grass-fed beef are good choices to ensure you are getting plenty of protein and the essential amino acids that your brain needs to function well.

For plant-based sources of protein, organic tofu, tempeh, beans and lentils can be enhanced with spices for flavor.

5. Nuts and seeds

Nuts and seeds have healthy omega fats and oils that will help sharpen your brain. They also have key vitamins and minerals, like selenium in Brazil nuts. Seeds like flax, chia and hemp are perfect options, too

I recommend eating about a quarter-cup or two ounces daily, either as a snack, or added to your salad or vegetable side dish.

Or you can throw some into a homemade granola or trail mix that contains much less sugar and salt than store-bought versions.

6. Fiber-rich foods and fermented foods

Fiber is important for your gut health, can help keep your weight in balance, and decreases inflammation in the entire body. Some high-fiber foods include artichoke hearts, quinoa, edamame, berries and pears.

Fermented foods like kefir, miso, and kimchee are also great for your brain and gut since they're a natural source of active cultures bacteria, and have been shown to lower inflammation.

7. Oils

While you want to avoid an excess of saturated fats and unhealthy oils like the kinds used for frying, you want to ensure you're getting enough healthy fats from sources like olive oil, avocados and oily fish.

Even with healthy fats, be aware of portion size and try not to eat too much. All fats are calorie dense.

8. Omega-rich foods

Important brain-boosting omega-3 fatty acids are found in fish like salmon, mackerel, and tuna.

Plant-based foods like chia seeds, Brussels sprouts, walnuts and flaxseeds are also rich in omega-3s.

9. Dairy

If you eat dairy, yogurts and kefir with probiotic cultures can do wonders for your gut, thanks to all the helpful bacteria and protein they contain. Grass-fed dairy products are better options for your brain, too.

Remember that certain conditions, like ADHD, can be aggravated by dairy, so be aware of how it affects you.

10. Spices

Spices are a no-calorie, guilt-free way to boost flavor in all your foods while adding beneficial brain effects.

Specifically, spices like turmeric, black pepper, saffron, red pepper flakes, oregano, and rosemary should be part of your brain armor.

Dr. Uma Naidoo is a nutritional psychiatrist, brain expert, and faculty member at Harvard Medical School. She is also the Director of Nutritional & Lifestyle Psychiatry at Massachusetts General Hospital and author of the best-selling book "This Is Your Brain on Food: An Indispensible Guide to the Surprising Foods that Fight Depression, Anxiety, PTSD, OCD, ADHD, and More." Follow her on Twitter @DrUmaNaidoo.

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A Harvard brain expert eats these 10 grocery foods to stay 'sharp and focused'—at any age - CNBC
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