Belonging to the Linaceae family, flaxseeds are small seeds that are golden yellow to reddish-brown in color, harvested from a blue flowering plant. Flax has been documented as a harvested crop in ancient Chinese and Egyptian cultures. It has been used in traditional medicine for its laxative and skin-healing properties. As a dietary source of healthy fats, antioxidants, fiber, vitamins, and minerals, flaxseed encompasses the meaning of "food as medicine." Keep reading to learn about the many reasons why flaxseed should be incorporated into a healthy diet. (3, 12, 18)
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Flax Seed 101: Nutritional Composition
Flaxseed (Linum usitatissimum) boasts an impressive nutritional profile, packed with essential nutrients that contribute significantly to overall health and well-being.
Flaxseeds contain about 55% alpha-linolenic acid (ALA), making them the richest plant source of this type of omega-3 polyunsaturated fatty acid. ALA is a healthy fat with anti-inflammatory, antithrombotic, and antiarrhythmic properties, making it an essential nutrient for heart health. (21, 27)
In addition to its healthy fat content, flaxseed is rich in lignans, containing 75-800 times more lignans than other plant foods. Lignans are polyphenolic compounds classified as phytoestrogens, meaning they have a similar chemical structure to human estrogen. When consumed, lignans can be converted by bacteria in the colon into enterolignans, enterodiol, and enterolactone, which are the bioactive forms that provide numerous health benefits. Not only do lignans act as potent antioxidants, they can also mimic, modulate, or block estrogen in the human body. (19, 27)
Flaxseed is an excellent source of dietary fiber, comprising 25% soluble fiber and 75% insoluble fiber. Soluble fiber absorbs water and slows digestion; it is also known to lower cholesterol, stabilize blood sugar, and reduce the overall risk of heart disease. Insoluble fiber increases the bulk of stool, promoting bowel regularity. (27)
Additionally, flaxseed contains 28–30% protein, making it a comparable plant-based source of protein to soybeans. It is a valuable option for vegetarians and vegans looking to meet their protein needs. (19, 21)
Flaxseed also offers a range of essential vitamins and minerals, including B vitamins (such as thiamine and niacin), magnesium, phosphorus, potassium, and calcium. These micronutrients are vital for various bodily functions, including energy metabolism, growth, and development. Micronutrient deficiencies can lead to potentially serious health problems and deficiencies; therefore, ensuring adequate dietary intake is important for achieving optimal health and preventing disease.
Top Therapeutic Uses of Flax Seed
The medicinal benefits of flaxseed are attributed to the nutritional components of the seed and seed oil discussed above. Regular consumption of flaxseed is associated with numerous health benefits, ranging from reduced cancer risk to improved digestion.
1. Cardiovascular Health
The American Heart Association (AHA) recognizes that adding flaxseed to the diet may help mitigate heart disease risk, given its rich fiber, ALA, and lignan content.
One of the key advantages of flaxseed for cardiovascular health is its ability to reduce blood pressure. Multiple clinical trials have shown that flaxseed consumption can decrease blood pressure in patients with hypertension. In one study, participants with hypertension consuming 30 grams of milled flaxseed daily displayed significant reductions in systolic (-10 mmHg) and diastolic (-7 mmHg) blood pressure after six months. Whole flaxseed consumed for at least 12 weeks appears to be the most effective form of flax for lowering blood pressure. (22)
Moreover, flaxseed has demonstrated its efficacy in improving carbohydrate metabolism and stabilizing blood sugar levels. Attributed to its high fiber content, flaxseeds slow down the absorption of sugar into the bloodstream (27). Clinical research shows that flaxseed consumption lowers insulin and blood glucose levels and may improve insulin sensitivity in adults with prediabetes and diabetes (26).
Whole and ground flaxseed modestly reduces lipid levels. Research shows that taking various flaxseed preparations at 30 grams daily reduces total cholesterol by 11% and low-density lipoprotein (LDL) cholesterol by 15% after just one month. Apolipoprotein B (ApoB), associated with increased risk of cardiovascular disease, has also been reduced by 7.5% after three months in postmenopausal women supplementing 40 grams of ground flaxseed daily.
2. Digestive Health
Flaxseed's high content of dietary fiber, both soluble and insoluble, is pivotal in promoting digestive wellness. The soluble fiber in flaxseed absorbs water, forming a gel-like substance that softens stools and facilitates their passage through the intestines, thus preventing constipation and promoting regular bowel movements. The gut microbiota also metabolizes soluble fibers into short-chain fatty acids (SCFAs), which are protective against digestive disorders, including inflammatory bowel disease and irritable bowel syndrome. Meanwhile, the insoluble fiber adds bulk to the stool, preventing diarrhea and ensuring proper elimination. (27)
Clinical trials and research studies have substantiated these benefits, providing empirical evidence for the efficacy of flaxseed in improving digestive health. Participants in these trials experienced enhanced bowel regularity and reduced instances of constipation following the incorporation of 20-25 grams of flaxseed daily into their diets for 4-12 weeks (11, 31).
3. Cancer Prevention
Lignans exhibit anti-cancer properties through several mechanisms. They possess antioxidant properties, neutralizing harmful free radicals that can damage cells and contribute to cancer development. Additionally, lignans can modulate hormone levels in the body, particularly estrogen, potentially reducing the risk of hormone-related cancers like breast and prostate cancer. Furthermore, lignans may interfere with cancer cell growth and division, promoting apoptosis, a process leading to the natural death of cancer cells, thereby inhibiting tumor progression. (27)
Numerous clinical trials and research studies have explored the impact of flaxseed on cancer prevention, yielding promising results. A comparative analysis of food frequency questionnaires from 2,999 women diagnosed with breast cancer and 3,370 healthy counterparts exposed the link between regular consumption of flaxseed and a decreased risk of breast cancer. In a clinical study, postmenopausal women newly diagnosed with breast cancer ate muffins containing 25 grams of flaxseed daily for 40 days. At the study's end, tumor cell proliferation markers were reduced, suggesting flaxseed's potential in reducing breast cancer tumor growth.
Preliminary research from animal and human studies also suggests flaxseed may positively affect prostate and colon cancer. However, more human clinical trials are needed to fully understand flaxseed's effects on the development and growth of these cancer cell types.
4. Inflammation Reduction
The anti-inflammatory benefits of flaxseed have been attributed to its rich content of ALA and antioxidant lignans, phenolic acids, and tocopherols (27). Clinical trials and research studies have provided substantial evidence supporting flaxseed's efficacy in combating inflammation. These trials have demonstrated that regular consumption of flaxseed leads to a significant decrease in markers of inflammation within the body, including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α).
It is understood that inflammation is a driving force of chronic disease. By inhibiting the production of these inflammatory markers, flaxseed helps mitigate the risk of chronic inflammatory disorders, providing a natural and accessible means to promote overall health.
5. Hormonal Balance
Flaxseed's role in balancing hormones and managing hormonal-related symptoms, particularly in women, has been a subject of extensive research and clinical interest. Rich in phytoestrogens, flaxseed interacts with estrogen receptors in the body. This interaction can help correct estrogen imbalances related to hormonal symptoms, such as hot flashes, insomnia, vaginal atrophy, depression, and anxiety (5).
Clinical research in postmenopausal adults shows that consuming flaxseed reduces menopausal symptoms; hot flashes have been reported to be reduced by 35% and night sweats by 44%. (9, 15)
A small clinical study in patients with polycystic ovary syndrome (PCOS) showed that taking 30 grams of flaxseed daily for 12 weeks, in conjunction with lifestyle modifications, not only reduces markers of cardiometabolic health, but also normalizes irregular menstrual cycles.
Incorporating Flax Seed into Your Diet
Incorporating flaxseed into your diet can be a flavorful and nutritious addition to your daily meals.
Flaxseed Forms
Whole flaxseeds have the longest shelf life but can be challenging for the body to break down. To unlock the full nutritional potential of flaxseed, it is advisable to grind whole seeds using a grinder or food processor before consumption. (19)
Pre-ground flax seed has a shorter shelf life than whole seeds; store milled seeds in the fridge or freezer to prevent them from spoiling. (19)
Flax oil is rich in the seed's fatty acids, but lacks fiber. (19)
Adding Flaxseed to Meals
For whole seeds, try sprinkling them on top of yogurt or cereal for a crunchy texture, or adding them to a smoothie.
Ground flaxseed meal can easily be mixed into smoothies, oatmeal, or baked goods like muffins and pancakes, boosting fiber and omega-3 fatty acids. Ground flaxseed is commonly used as an egg replacement. To replace one egg in a recipe, mix 1 tablespoon of ground flaxseed with 3 tablespoons of water and let it sit for 3-5 minutes until it has formed a gel-like consistency. (12)
Alternatively, flaxseed oil can be used as a salad dressing or drizzled over roasted vegetables for a nutty flavor. Flaxseed oil has a low smoke point, so avoid using it to cook at high temperatures. (12)
Precautions and Side Effects
Ground flaxseed has been used safely in numerous clinical trials in doses of up to 60 grams daily. For some, excessive consumption of flaxseed may lead to digestive issues, such as bloating, gas, and abdominal discomfort, due to its high fiber content. Raw and unripe flaxseeds may be poisonous and should not be eaten. (17)
As with any source of fiber, ground flaxseed should be taken with plenty of water to prevent constipation (17).
For those with certain health conditions, such as digestive disorders or a history of intestinal blockages, caution is advised when incorporating flaxseed into the diet. The high fiber content might exacerbate symptoms or cause complications in these cases. Furthermore, individuals taking blood-thinning medications or with bleeding disorders should consult their healthcare provider before consuming flaxseed, as its omega-3 fatty acids may have anticoagulant effects. (17)
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Summary
Integrating flaxseed into your daily routine can be a game-changer for overall health and well-being. Its versatility shines through in various forms, from whole seeds to ground meal and oil, making it easy to integrate into a wide range of dishes. Beyond its nutty flavor, flaxseed offers many health benefits, including heart-healthy omega-3 fatty acids, digestion-boosting fiber, and cancer-fighting lignans. By including flaxseed as part of a balanced diet, you're not just enhancing the taste of your meals; you're also providing your body with essential vitality-promoting nutrients.