Harvard nutritionist eats these 5 foods to keep her ‘immune system strong' and ‘energy high'

You may feel ready for spring, but we have a solid stretch of winter still ahead of us, and our immune systems continue to be put to the test every day. There are colds and flus and other viruses still going around. And many of us also feel a strain on our mental health with less mood-boosting sun exposure.

You might be drawn to various supplements and feel more inclined to reach for comfort foods. But as a nutritional psychiatrist, I know these aren't necessarily the best options for keeping the body and mind strong throughout the colder, darker days of the winter season.

We're incredibly dependent on the health of the gut, which houses about 70% of the immune system. Similarly, our mental fitness is impacted by the health of the microbiome via the gut-brain connection. 

That's why I always recommend people take extra good care of their gut this time of year. It's what I do to maintain my own wellbeing — making intentional and mindful dietary choices.  

Here are some of the top foods I'll be leaning on for the rest of the winter to keep my immune system strong, my energy levels high, and my mood bright.

1. Citrus fruits

Lemons, limes, oranges, grapefruits, and more! Citrus fruits are an excellent source of antioxidant vitamin C and contain a good amount of fiber. This combination supports the gut, brain, and immune system.

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I love adding lemon to my afternoon green tea ritual. I use a squeeze of fresh lemon and lemon zest on my salads. If I have clementines, I add a few segments of those to my salad, too. I also love making a lemon vinaigrette to add to roasted vegetables — a staple of my daily meals.

2. Leafy greens

Leafy greens are essential in my diet and I try to eat several servings each day.

I love my daily salad, for example, and add as many colors and textures as I can to change it up. In the winter, it's quick and easy to toss in some spinach just before eating my favorite Tuscan bean stew so the leaves meld into the hot liquid. And I make crispy chips out of baby spinach and kale for a great afternoon snack.

These leafy greens are loaded with folate, a B vitamin that helps to regulate neurotransmitters in the brain and has been linked to a reduced risk of depressive symptoms. They're also a great source of fiber to keep my microbiome balanced and the immune system strong. 

3. Clean proteins

Protein-rich foods like wild-caught salmon, organic tofu, grass-fed beef, pasture-raised eggs, and poultry are rich in B vitamins. This group of vitamins is so important for the nervous system, I try to make protein-rich foods part of my diet year-round. During the gloomy winter months, getting enough B vitamins can help optimize my mood and vibrancy. 

I toss organic tofu with my grandmother's masala spice blend and crisp it up in the air fryer. I like to add spicy chickpeas and legumes to my soups or salads too. By changing up the spices, I can enjoy South Asian, Mexican, Greek, and other flavors. 

If you choose not to consume animal products, you may consider supplementing vitamin B12 or adding nutritional yeast to your diet, but always discuss with your doctor first.

4. Fermented foods

These include sauerkraut, kimchi, miso, plain yogurt, and kefir, among others. Fermented foods are naturally rich in live strains of good bacteria.

I incorporate these into my daily meals throughout winter for the health of my microbiome and the delicious flavors. I love adding kimchi to my daily salad or making miso-glazed sweet potatoes — one of my favorite recipes that I developed for my first book, "This Is Your Brain on Food."

5. Spices

Especially during colder seasons, I love having lots of warming spices in my diet. Turmeric, black pepper, cinnamon, ginger, saffron and cayenne pepper are all loaded with micronutrients and antioxidants. They may help reduce the chronic inflammation that is associated with low mood and poor immunity. 

I particularly enjoy sipping on a cup of golden milk, a.k.a. a turmeric latte, and add spices into whatever other foods and beverages I'm already making, including roasted vegetables, salad dressings, tea, smoothies, and even healthy-ish desserts. 

Dr. Uma Naidoo is the MoodFoodMD, a Harvard-trained nutritional psychiatrist, professional chef, and nutritional biologist. She's an instructor at MasterClass and the author of "Calm your Mind with Food" and the national and international bestseller "This is Your Brain on Food."

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