Just the Flax
August 1, 2007
Flax use is on the rise. Data-monitor, New York, reports significant growth in the introduction of new flax-containing foods and beverages in North America, from about 220 in 2000 to 630 in 2005. According to the Flax Council of Canada, Winnipeg, Manitoba, the bread and cracker category accounts for more than 20% of total U.S. flaxseed sales, while cereals represent between 8% to 10% of sales. In dairy, flax oil is most commonly used in spreads and milk beverages to provide 300 mg of omega-3 per serving, which is required for a nutrient-content claim. In the prepared foods category, flax is found in products such as pasta.
It’s becoming popular with good reason: Flax contains approximately 40% fat, 28% dietary fiber, 21% protein, 4% ash and 6% carbohydrates, such as sugars, phenolic acids, lignans and hemicellulose. It possesses a unique nutritional composition of omega- 3 fatty acid, phytoestrogens, antioxidants and fiber, and provides a nutritious plant protein, with an amino-acid composition similar to that of soy protein.
Healthy flaxseed fats
Flax has a singular and healthy fatty-acid profile, with very low saturated fat (approximately 9%) and moderate amounts of monounsaturated fat (approximately 18%). Of the nutritionally beneficial polyunsaturated fats, about 16% belong to the omega-6 family as linoleic acid (LA), and 57% is the omega-3 fatty acid, alpha-linolenic acid (ALA).
The omega-6 and omega-3 fatty-acid families act as precursors for different series of hormone-like substances known as eicosanoids. Omega-6-derived eicosanoids stimulate proinflammatory, prothrombotic and hypertensive events. Eicosanoids synthesized from omega-3 fatty acids have opposite effects. For optimal health, Health Canada, Longueuil, Quebec, recommends an omega-6 to omega-3 fatty-acid dietary ratio of 4:1 to 10:1. It is speculated that
Western diets may have ratios of omega-6 to omega-3 fatty acids as high as 20:1 or even 30:1. Flaxseed contains an omega-6 to omega-3 ratio of 0.3:1.
Currently, the United States has not established a Recommended Dietary Allowance (RDA) for omega-3 fatty acids. However, the Institute of Medicine (IOM) of the National Academies, Washington, D.C., recommends 1.6 grams per day of ALA for men, and 1.1 grams per day for women.
Flax on fiber
Total fiber accounts for about 28% of the weight of full-fat flaxseed, and is found in both soluble and insoluble forms. Water-soluble fibers, such as flax’s mucilage, delay transit through the stomach and small intestine. The hydration characteristics of mucilage gums trap lipids and aid in excretion, thus helping to lower serum cholesterol levels, an effect that ultimately benefits cardiovascular health. Fibers that are predominantly water insoluble promote laxation and are either slowly fermented or not fermented at all. Diets high in insoluble fiber promote good colon health, which may have protective effects against colon cancer.
One tablespoon (10.3 grams) of whole flax contains 600 mg to 1.2 grams insoluble fiber, and 1.8 to 2.4 grams soluble fiber; milled flax contains 440 to 880 mg insoluble fiber, and 1.3 to 1.8 grams soluble fiber per tablespoon.
Lowdown on lignans
Lignans are phytoestrogens, estrogen-like compounds found in plants. Flax contains 75 to 800 times more lignans than any other vegetable, fruit, legume, cereal or seed. These compounds show promise in reducing growth of cancerous tumors, especially hormone-sensitive tumors, such as those of the breast, endometrium and prostate.
Flax lignans also play an important role in reducing the risk of diabetes. In one study, volunteers who consumed 50 grams of carbohydrates from bread containing flaxseed showed significant improvements in glucose absorption (American Journal of Clinical Nutrition, 1995; 61:62-68). A separate study showed the consumption of 40 grams of ground flaxseed for a two-month period also reduced postprandial blood glucose, insulin and serum lipid levels (British Journal of Nutrition, 1993; 69:443-453).
The powerful antioxidant properties of lignans, as well as phenolic acids and flavanoids found in flax, can reduce the activity of cell-damaging free radicals generated through oxidation in the body, which are strongly associated with aging. Antioxidants in flax are so effective that, synergistically, they help stabilize fish oils—a relationship flax ingredient suppliers are exploring.
Flax nutrients battle CVD
Intervention studies have shown beneficial effects of ALA on cardiac health. In the Health Professionals Follow-up Study, a 1% increase in ALA intake (as percent of energy) has been associated with a 40% reduction in the risk of nonfatal coronary heart disease (British Medical Journal, 1996; 313:84-90).
Recent research is focusing on the role ALA can play in lowering inflammatory biomarkers. A study published in the European Journal of Clinical Nutrition (2004, 58:1083-1089) showed a diet high in ALA dramatically decreased C-reactive protein in men and women with high cholesterol levels.
Flax nutrients also offer protection against CVD. Consuming milled flax at levels of three to six tablespoons (30 to 50 grams) for as little as four weeks reduced blood total and low-density lipoprotein cholesterol significantly in clinical trials.
Formulating with flax
ALA and lignans in flax remain stable under common baking temperatures of 178ºC (350ºF). Milled flax can substitute for fat at a ratio of 3:1, and also can replace some of the flour in baked goods.
Interesting, innovative flax ingredients are available to food and beverage manufacturers, including various grinds of highly stable milled flax. Also available are milled flaxseed products blended with ingredients such as cranberry, apple or blueberry powder, or probiotics. A new entry to the food-ingredient market is a granulated, free-flowing powder of milled flax combined with either 2.2% or 8.0% fish oil.
Kelley Fitzpatrick, M.Sc., is director of health and nutrition for Flax Canada 2015. She can be reached at [email protected].
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