AHA News: Know the Flax: A Little Seed May Be What Your Diet Needs

FRIDAY, July 19, 2019 (American Heart Association News) -- Adding seeds to your diet can be an easy way to shore up your defenses against heart risks without adding too much work to meal prep.

Many types of seeds can be valuable as part of a healthy diet – commonly added as a snack or add-on to salads or desserts – because they are rich in nutrients. You also can find seeds baked into breads or crackers, or even in some fruits and vegetables.

Flaxseed and chia seeds, in particular, have been linked to good heart health because their nutrients pack a powerful punch.

"Flaxseeds or chia seeds offer good sources of alpha-linolenic acid (ALA), which are unsaturated fatty acids that convert to omega-3 fatty acids typically found in fish," said Linda Van Horn, a registered dietitian and professor in the department of preventive medicine at Northwestern University in Chicago. "But they also offer a good plant-based supply of plant-based proteins, fiber, minerals and other nutrients."

Specifically, flaxseeds contain lignans, a natural chemical compound that along with fiber, antioxidants and healthy fats can help reduce blood cholesterol and may also help lower blood pressure. Some studies suggest lignans may have the potential to reduce tumor growth in women with breast cancer and may protect against prostate cancer.

Chia seeds, which contain many of the same nutrients found in flaxseeds, can help lower the blood sugar response to eating. Chia seeds also may serve as an appetite suppressant because of their high fiber content.

Other seeds such as hemp, sunflower, pumpkin or sesame seeds are highly nutritious as well. Federal dietary guidelines include seeds and nuts as a good source of protein and part of a healthy diet. When incorporating them into meals, it's important to choose seeds that are prepared in a healthy manner, Van Horn said.

"There are no 'wrong' seeds, just unhealthy packaging, including added salt, sugar or fat," she said. "Better to use seeds in a natural or toasted state, like nuts, or blended into baked goods, cereal or mashed as a paste, like tahini from sesame seeds."

Because they are easy to eat by the handful, Van Horn said, it's wise to introduce them to your diet carefully.

"Seeds are high in fiber and require lots of fluid to fully digest them properly," she said. "Problems with constipation or diarrhea can occur if too much is consumed too fast without fluid."

Additionally, research shows chia seeds swell in size when exposed to too much water, so moderation is important.

"Also, it is easy to overeat seeds and experience weight gain if not careful in factoring in these calories," Van Horn said.

A 1-ounce serving of whole flaxseed contains 150 calories, 7.6 grams of fiber and 6.4 grams of omega-3 fats. A similar-sized serving of chia seeds contains 137 calories, 10.6 grams of fiber and 4.9 grams of omega-3 fats.

Because of their size, seeds could be harmful among people who have been diagnosed with irritable bowel disease or diverticulitis, Van Horn said.

"Problems occur when particles get trapped in certain folds or 'outpouches' within the intestinal track that can become irritated and inflamed as a result of these conditions. Better to check with your doctor if you suffer from any of these conditions," she said.

"Most such patients have been advised to avoid any foods with seeds, including strawberries, blueberries or sesame seeds or other small particles of this size."