Like many patients who come to my Manhattan office, you may not think of yourself as allergic. Your nose may not run and your skin doesn't itch. But you have complaints that just won't go away.

If you experience weight gain, stomachaches, insomnia, headaches, fatigue, depression, anxiety, or brain fog, a hidden allergy might be the culprit. My clinical experience and search for answers to common mystery conditions inspired me to write my new book The Allergy Solution: Unlock the Surprising, Hidden Truth about Why You Are Sick and How to Get Well with my son Jonathan Galland.

Only 50 years ago, one in 30 people had allergies. Today, that figure is more like one in three. The allergy epidemic sweeping the world is getting worse, with well over one billion people suffering from allergies.

An Immune System Out of Balance

Allergies result from an immune system that is out of balance. Our bodies are reacting in a forceful way to the modern world, and fast food, stress, mold, chemicals, pollution, and poor gut health are fueling the rise in allergies. Each of these can interfere with your immune system, especially with the cells that naturally prevent allergies. They’re called regulatory T-cells, or T-regs . My program is designed to help you balance immunity by restoring the power of your T-regs.

Let’s explore some of the leading causes of allergies and what you can do to get well.

Air Pollution Increases Pollen Counts

Pollen counts are going up each year. Why? Air pollution is a big part of the problem. Scientists at the U.S. Department of Agriculture investigated how air pollution affects ragweed. They discovered that pollution makes the plants grow twice as large and produce five times more pollen. Many types of pollen, especially ragweed, are toxic. They contain an enzyme that damages the lining of your nose and lungs when you breathe them in. This sets the stage for allergies.

Air Fresheners Boost Allergy Risk

Air fresheners increase risk of allergies and asthma, mostly because of the chemical fragrances they contain, reports a study from the University of California. So what’s the alternative? I can’t think of a better way to freshen your home or office than with proper ventilation. Open your windows regularly to let fresh air in. If the air outside your home is actually worse than the air inside, try a commercial air purifier.

Many cleaning sprays are also hazardous to your health. Studies report that using a household cleaning spray just once a week elevates your risk of developing asthma by 30 to 50 percent. Try natural alternatives to cleaning spray instead. At home we use water and baking soda for most cleaning jobs. Vinegar and water is great for glass and tile.

Fast Food Causes Allergies

A large international study found it only takes three fast food meals a week to increase allergies. Why? It’s the unhealthy fats and sugar and what you don’t get from fast food: vitamins, minerals, flavonoids, carotenoids, as well as other phytonutients that are necessary for balancing immunity.

How can nutrients help? Scientists at UCLA looked at the effect diesel exhaust fumes had on people with pollen allergies, and found that diesel fumes tremendously increased the allergic response. Next, they fed them broccoli, and within three days, the food blocked the ability of air pollution to aggravate the allergic reaction.

What’re more, allergic reactions can make your fat cells grow larger. As fat cells expand, they unleash stronger allergic reactions. The allergy fighting Immune Balance Diet in my program combats allergies by supporting your body’s resistance to inflammation.

It’s easy to follow: just add something from each of these categories to your daily menu: delicious fruits like strawberries, blueberries, mangoes, and papaya; colorful vegetables like spinach, avocado, sweet potato, carrots, broccoli, arugula, and kale; tangy herbs and spices like parsley, scallions, garlic, ginger, and turmeric.

Beat Brain Fog and Restore Your Energy

Indoor allergens, such as mold and other toxins, are common hidden allergens that often provoke severe fatigue and brain fog.

Mold is a dangerous indoor toxin. Tips to avoid it:

  • Investigate damp locations in your home and plug any leaks.

  • Get rid of things that attract mold, like furnishings that are damaged by water.

  • Clean shower stalls and curtains, where mold grows, with a non-toxic solution. Hydrogen peroxide in water works well.

  • Keep humidity at under 50 percent in each room of your home, using a dehumidifier if necessary.

Unlock Your Allergies from the Inside Out

Your gut is the largest part of your immune system. It is home to trillions of bacteria, which play an important role in balancing immunity. That is why the gut is central to allergies. A well-functioning gut protects you against allergens and toxins circulating in your digestive system.

Gut bacteria have a major impact on immune function; like a rainforest, biodiversity is a sign of health. And scientists have found that diminished diversity of gut microbes is an important risk factor for allergies. How can you maintain a healthy diversity of bacteria?

Eat a varied, high-fiber diet with lots of fruits and vegetables. The nutrients that naturally give food its vibrant colors are called flavonoids. They help fight allergies and encourage the diversity of bacteria. Fermented foods like sauerkraut, yogurt, and raw foods also increase diversity of gut bacteria. If you eat meat, organically raised farm animals that don't get antibiotics are the wise choice.

Finally, unless you’re washing up before surgery, avoid antibacterial soaps and shampoos. They just encourage the growth of resistant organisms and kill healthy bacteria. Probiotics, the healthy bacteria from yogurt or supplements, can relieve symptoms of allergies by improving immune responses.

Leo Galland, MD, is a world leader in integrated medicine and a founder of Functional Medicine. Educated at Harvard University and the NYU School of Medicine, he won the Linus Pauling Award for his trailblazing vision that created a bold new way to practice medicine for thousands of doctors. In the groundbreaking new book, The Allergy Solution: Unlock the Surprising, Hidden Truth about Why You Are Sick and How to Get Well , Dr. Galland and Jonathan Galland, J.D., reveal the shocking rise of hidden allergies that lead to unexplained weight gain, anxiety, fatigue, depression, and other mystery symptoms. In this book they show us what steps we can take to rebalance our immunity through nutrition and lifestyle to reverse allergies without drugs.