If you’re reading this, you’re likely feeling a little under the weather—or at least, you know you will be soon. Be it a lingering tiredness, a tickle in the back of your throat, or a nose that resembles an open tap, sick season is officially upon us.

Outside of stocking up on zinc-rich foods (an essential mineral for healthy immune function) and getting enough sleep, there are a couple of other expert-approved ways to ward off the winter lurgy. Here, three nutritionists share their best advice for staying well, from smart supplements to fortified gut health.

1. Prioritize antioxidants

“Some nutrients support the optimal functioning of immune cells, like vitamin C,” says W-Wellness nutritional therapist Maz Packham. “It’s a powerful antioxidant that’s needed for our white blood cells to defend the body against infection.”

Her suggested sources of vitamin C include:

• Kiwis
• Citrus fruits like lemons and limes
• Berries
• Peppers

2. Think color

When in doubt, add in as much (natural) color as possible to your daily diet. Fruits, vegetables, and plants like red cabbage, pumpkin, and squash are rich in immune-supporting nutrients like vitamin C, beta carotene, and zinc, says nutritionist and functional medicine practitioner Farzanah Nasser.

She likes to mix things up by incorporating pumpkin into delicious loaves of bread, adding root vegetables to soups made with bone broth and taking advantage of the antiviral nature of matcha.

3. Stock up on vitamin D

Low levels of vitamin D are linked to increased susceptibility to infection, along with low mood and fatigue, Packham describes. “Include oily fish and eggs in your diet and consider supplementing with a vitamin D supplement,” she advises. Because of winter’s limited sunlight and the fact that we get very small amounts through our diet, a good quality supplement can be an efficient way to boost levels.

4. Focus on fiber

For top marks, aim to eat 30g of fiber per day. “Fiber helps nourish our gut microbiome, which trains our immune cells and keeps us healthy,” Nasser explains. “Up to 80% of the immune system lives in the gut—including more fiber is a really simple way to look after your immunity.”

One very easy way to eat more fiber is to add seeds to your diet. Chia and flax are two options that work well stirred into yogurt or sprinkled onto porridge—or try editor Margaux Anbouba’s favorite, Zoe’s Daily30+ blend, which has 30 seeds in a single scoop. Beans, like chickpeas, are rich fiber sources, too. The goal is consistent, adequate fiber throughout the day—which helps with blood sugar control, satiety, and efficient elimination.

5. Include fermented foods

Fermented foods contain good microbes (which add to the microbes already present in the gut), creating a varied environment for a healthy gut environment to flourish. “One study showed that the lactic acid bacteria and fermentation metabolites in kimchi can even inhibit the flu virus,” Nasser suggests.

Her best advice is to include some form of fermentation in each of your meals. This could look like eating yogurt or kefir for breakfast, mixing some apple cider vinegar into your salad dressing at lunch, and sipping a kombucha at your evening meals. Sauerkraut, pickles, miso, and tempeh are all worthy options, too.

6. Sleep and nature are medicinal

Our immune health is hinged largely on how well we rest and how much we stress. Reducing the latter and improving the former can help protect the body against an influx of bugs by lowering inflammation and bringing the nervous system and body back from the brink.

The other trick, Nasser says, is to get outside. “When we go for walks or spend time in nature, we actually breathe in immune-supporting chemicals released by the trees and plants.” These chemicals, phytoncides, trigger the body’s parasympathetic nervous system (rest and digest) and help to lower cortisol levels. They also increase the number of Natural Killer cells, which target virus-infected or abnormal cells, explains Nasser.