One way to include more heart-healthy polyunsaturated fats in your diet is by replacing some servings of meat and poultry with seeds–they’re not just for birdfeeders! An example would be using a small amount of seeds like chia, flax, pumpkin, or hemp as toppings on salads or soups. Since they are high in calories, eat them in small portions. Seeds are especially important for individuals who do not consume meat or poultry because seeds also contain essential amino acids and minerals, including zinc, copper, and magnesium.
Recently, chia and flax seeds have received particular attention due to their uniquely high amounts of omega-3 fatty acids, a type of polyunsaturated fat. You may have even seen statements in blog posts or on food labels about a serving of chia or flax seeds containing more omega-3s than a serving of fish. Although this might be true, the type of omega-3s in plant foods differ from those in oily fish. This distinction is important to understand if you want to ensure you’re reaching recommendations for omega-3s.
The bottom line
Chia seeds and flax seeds are sources of healthy fats, but our biology limits their conversion to useable omega-3s in the body. So, claims about the omega-3 content of chia and flax seeds might not be what they seem. Despite this distinction, seeds are still nutritious whole foods that can contribute nutrients like fiber, protein, minerals, and antioxidants to your daily diet. Just don’t plan on seeds being your only source of omega-3s if you can occasionally include oily fish too.
For more detail, read on!
Chia and flax seeds stand out from others because they are strong sources of a fatty acid called alpha-linolenic acid, abbreviated ALA. ALA is the form of omega-3s found in plants. One tablespoon of chia seeds has 2.4 grams of ALA. A similar-sized serving of ground flaxseeds has 1.9 grams. There are two other types of omega-3s important to our health called EPA and DHA. Non-fried oily fish, including salmon, trout, herring, mackerel, and sardines are the best sources of EPA and DHA. When you read or hear about the health benefits of omega-3s, they are likely referencing those found in oily fish—EPA and DHA.
The health benefits attributed to plant-based omega-3s (ALA) are available only after conversion to EPA or DHA in the body. Our livers have a limited supply of the enzymes that make the conversion to EPA and DHA possible, so the process isn’t very efficient. An estimated five-to-ten percent of ALA converts to active EPA, and only two-to-five percent converts to active DHA in the body. This means that, although a one-tablespoon serving of chia seeds or flaxseeds may contain as much as 2.4 grams of omega-3s, only about 0.05-0.24 grams might end up as useable EPA or DHA in the body. This conversion can be reduced further based on factors like age, gender, and intake of saturated fat and trans-fat. In comparison, a single three-ounce portion of salmon contains about one gram of active EPA and DHA available for direct absorption.
Omega-3’s role in health
EPA and DHA are known to generate anti-inflammatory eicosanoids that can help minimize the role of inflammation in chronic diseases like heart disease and type 2 diabetes. When it comes to lowering risk of heart disease, high blood levels of EPA and DHA are consistently shown to modestly reduce blood pressure, decrease blood clotting, maintain normal heart rhythm, and lower triglycerides as much as twenty-to-fifty percent. Some long-term observational studies have even linked diets high in EPA and DHA to a reduced risk of cognitive decline, Alzheimer’s disease, and dementia, possibly due to DHA’s role in maintaining neuron function in the brain.
On the other hand, the benefits of ALA separate from EPA And DHA are not as well documented. Research that has investigated ALA-rich diets have shown mixed and inconsistent results. Findings include potential to lower cholesterol and triglyceride levels, reduce blood vessel inflammation, and lower blood pressure, but only in people with already high cholesterol levels.
Getting enough omega-3s
There are no official EPA or DHA recommendations, but the standard advice is to increase omega-3 consumption from seafood. The American Heart Association, along with the most recent Dietary Guidelines for Americans, suggest eating 3-4 ounces of oily fish at least two times a week to ensure adequate omega-3 intake. Current research does not support omega-3 fish oil supplements over eating whole fish. In a 2018 systematic review, fish oil supplements showed little or no effect when it came to risk of heart disease, stroke, or death.
People who don’t eat fish and people who eat vegetarian or vegan diets should focus on eating ALA-rich foods. The National Academy of Sciences considers a daily intake of 1.1-1.6 grams of ALA nutritionally adequate. A one-tablespoon serving of chia or flax can help you meet these recommendations. However, avocado, soybeans, walnuts, pecans, beans, peas, soybean oil, and canola oil contain ALA too.
Purchase, store, eat – chia and flax
Eat chia seeds in their whole form, but purchase ground flaxseeds or grind whole flax seeds in a coffee grinder before consuming to enhance nutrient absorption. Chia seeds are best stored dry at room temperature. Keep ground flaxseed in the refrigerator or freezer instead of at room temperature to prevent their oils from going rancid.
When beginning to eat more chia or flax, keep in mind that they have lots of fiber. Fiber can cause temporary gas, bloating, or digestive system upset if you’re body isn’t yet accustomed to the daily 25-38-gram recommendation. Start with a one teaspoon serving and gradually add additional teaspoons in consecutive weeks until you reach a one-to-two tablespoon serving without discomfort. As your body adjusts to the beneficial fiber in these seeds, increase your water intake to reduce the chance of constipation.
The easiest way to use chia and flaxseeds is by sprinkling a small serving onto green salads, soups, plain non-fat yogurt, whole grain cereals, or whole-wheat toast with nut butter. In many baking recipes, up to 15% of flour can be replaced with ground flaxseed. Both seeds can be used to increase the fiber, nutrient content, and thickness of liquids like smoothies. Chia and ground flaxseed make great egg substitutes in baked goods. Try mixing three tablespoons of ground flax or whole chia seeds with three teaspoons of water and let sit for 3-5 minutes until thickened. Then, use as you would one egg in a baked good. Here are even more ways to enjoy flax and chia.