10 super-nutrients for a flat belly

There are many reasons to eat a nutritious diet — you want to fend off the nasty bug that’s going around, you want more energy, you want to improve your overall health. But here’s one incentive that will have you running to the produce aisle: a flatter belly.

If you’d like a toned tummy, sit-ups and calorie-counting will only get you so far. What you put into your body is just as important as how much you sweat off at the gym.

It’s no surprise that eating a salad will flatten your belly faster than, say, chili-cheese fries — but it’s not just because of the 1,000 calories you’ll save. Feasting on a healthy diet rich in nutrients like calcium, vitamin C and beta-carotene (to name a few) will help you lose inches around your middle and stave off a host of diseases. Start loading up on these powerhouse nutrients today.

1. Beta carotene and lycopene

•  What they are: Both are pigments found in plants and colorful vegetables, and both are high in antioxidant properties. Beta-carotene is converted into vitamin A in the liver.

•  Foods to choose: As a general rule, orange and yellow vegetables are rich in beta-carotene. Load up on carrots, sweet potatoes, spinach and other leafy green vegetables, and fruits such as cantaloupes and apricots.

Tomatoes are some of the richest sources of lycopene. (Bonus tip: According to a study at Cornell University, if you heat up tomatoes, it spikes the lycopene content and makes it easier for your body to absorb the nutrient.) You can get lycopene in tomato sauce and ketchup. Other sources of this important nutrient include watermelon, pink grapefruit and apricots.

2. Vitamin C

•  The belly-flattening science: In addition to boosting the immune system and helping to fight off colds, C plays a role in helping you get the physique you want. A recent study by the American Journal of Clinical Nutrition found the higher the vitamin C content in blood samples of participants, the lower the waist-to-hip ratio was for both men and women.

Vitamin C can also help you burn more fat. A 2006 study by the University of Arizona found that those with higher vitamin C in their system oxidized 25 percent more fat during the treadmill test than those with “marginal vitamin C status.”

•  Foods to choose: Green peppers, citrus fruits like oranges and grapefruit, strawberries, tomatoes, broccoli, leafy greens, sweet and white potatoes, and cantaloupe.

3. Vitamin D

•  What it is: This fat-soluble vitamin is naturally formed when our bodies are exposed to sunlight. But because most of us spend eight-plus hours inside, we rely on a small group of foods to provide the D vitamins our bodies need.

•  The belly-flattening science: There have been many recent studies touting the belly-banishing effects of vitamin D. Researchers at the Medical College of Georgia found teenagers who reported higher vitamin D intakes had lower amounts of abdominal fat and lower overall body fat. A 2010 study by the University of Michigan found that kids deficient in vitamin D accumulated fat around the waist and gained weight more rapidly than kids who got adequate amounts of the vitamin. But it isn’t just teens and kids who gain more weight when deficient in the sunshine vitamin: A 2010 study published in the Journal of Nutrition found the same inverse relationship, suggesting overweight folks may have problems processing the vitamin properly.

•  Foods to choose: Mushrooms, especially shiitake and button, and eggs. In addition, you can get high amounts of the vitamin in fish sources like mackerel, salmon, herring, sardines, catfish and tuna.

4. B vitamins

•  What they are: These water-soluble vitamins play an important role in cell metabolism. These nutrients are actually made up of eight different vitamins.

•  The belly-flattening science: B vitamins help beat the bulge by converting protons, fats and carbohydrates into energy — also increasing your metabolism. A study published in the International Journal of Sports Nutrition and Exercise Metabolism found that individuals with a lack of these vitamins performed worse during high-impact exercise than athletes with balanced levels of B-complex vitamins. Also, multiple studies show that those who lacked B vitamins experienced a decreased ability to repair and rebuild muscles.

5. Calcium

•  The belly-flattening science: A study published in Nutrition and Metabolism found that those who consumed 1,400 or 1,500 milligrams of calcium per day gained less body fat over a four-year period. In another study at the University of Tennessee, scientists found that those who ate three daily servings of calcium lost 70 percent more weight and 64 percent more body fat.

6. Omega-3 fatty acids

•  What it is: Omega-3s are polyunsaturated fatty acids. They are considered essential fatty acids your body can’t make alone — you have to gain these through your diet.

•  The belly-flattening science: Several studies published in the American Journal of Nutrition and the International Journal of Obesity suggest that 1.5 to 2 grams daily of fish oil can produce weight loss of a couple of pounds over a month or so. A study from the University of Georgia found that fish oils prevent pre-fat cells from being converted into fat. Also, researchers from the University of Navarra in Spain and the University of Iceland found that omega-3-rich foods keep people feeling full longer.

Research also shows omega-3 fatty acids lower levels of stress hormones, such as cortisol, that can contribute to fat storage.

7. Choline

•  What it is: Choline is a chemical similar to B vitamins and is often lumped in with them. Although choline is not by strict definition a vitamin, it is an essential nutrient and it can help reduce belly fat.

•  The belly-flattening science: Choline is known to play a role in the metabolism of fat — it breaks down fat for use as an energy source. Because of that, recent studies have shown choline, which is found in large amounts in egg yolks, to play a role in weight loss. A study published in the Journal of the American College of Nutrition found an egg breakfast induced greater satiety and significantly reduced short-term food intake compared with a calorically equivalent bagel breakfast.

•  Foods to choose: Eggs, peanuts, potatoes, tomatoes, bananas, lentils and milk.

8. Anthocyanins

•  What they are: These antioxidants are water-soluble vacuolar pigments that may appear red, purple or blue.

•  The belly-flattening science: A University of Michigan study found that those who ate berries high in anthocyanins, such as tart cherries and blueberries, had less belly fat. In a study performed on rats, researchers found animals that were fed cherry powder lost 17 percent of their belly fat in just three months. In a similar study using blueberry powder, researchers found that rats lost belly fat when fed blueberry powder, even in combination with a high-fat diet. Though the studies have only been conducted in animals, study authors are hopeful humans can experience the same belly-busting benefits.

•  Foods to choose: Beyond cherries and blueberries, load up on cranberries, oranges, radishes, raspberries, red onions, red grapes and wine.

9. Potassium

•  What it is: Potassium is a powerful electrolyte and occurs naturally in many foods.

•  The belly-flattening science: This nutrient is a little different from the others on this list but serves an important role in banishing belly fat. Here’s how: Too much sodium in your body can make you retain an excess of water, which in turn gives you that undesired Buddha-belly look. Eating potassium-rich foods triggers the kidneys to excrete more sodium. The nutrient has a diuretic effect on your body, which promotes the right water balance and helps you look more svelte.

•  Foods to choose: Bananas, avocados, spinach, sweet potatoes and papayas.

10. Fiber

•  What it is: Fiber is a type of carbohydrate that the body can’t digest.

•  The belly-flattening science: Fiber-rich foods are typically low in calories but keep you feeling full longer. Fiber also helps maintain an even blood-sugar level, which helps prevent you from overeating during mealtimes. A study from the University of Southern California found that participants who added 6 grams more fiber to their diet every day helped shrink their belly fat by 4 percent.

•  Foods to choose: Whole-grain foods, nuts and seeds, avocados, broccoli, cabbage, carrots, raspberries, pears and apples.

This story was originally published August 10, 2012 at 5:00 AM.