I was recently asked a few questions about flax seeds. Specifically, the question were 1) is there any nutritional reason (or any other reason) to prefer using either the brown flax seed or the golden flax seed ? 2) What is the best way to store them?

Well, like with many things, there are many misconceptions about flax seeds in regard to these two issues, and as usual, some of it is based on misinformation that comes from marketing and advertising.

In regard to the color difference, as you may know, you can show some minor difference between the different colored varieties of any foods and this is true whether it is apples, pears, etc. However, there is really little difference between the different varieties of flax seeds

From the Flax Council, which supports the growth and sale of both..

"The color of flax has no bearing on its nutritional value, despite claims by its growers that golden flax is superior. In tests conducted by the Canadian Grain Commission in the summer of 2001, the "Dakota Gold" flax from South Dakota was shown to have 43-44% oil content, while the Canadian brown flax tested had 44%, virtually the same.

However, the level of ALA (Alpha Linolenic Acid -- source of Omega 3 fatty acids) in the Canadian brown seed was 59% of the oil, compared to 51% in the "Dakota Gold". This difference is due to the colder Canadian climate, and perhaps better soil quality, not the color variety. 
Both the Canadian brown and "Dakota Gold" flax are superior in oil content to other flax grown in the U.S. which has far less oil. However, unlike any other North American flax, Northern Edge® Flax seed is free of toxic cadmium; and it is the only flax seed tested to ensure the highest ALA oil level as well as purity from contaminants.

Further, golden flax is a hybrid plant. Hybrids are generally weaker than standard varieties of a plant, and usually do not absorb nutrients from the soil as well. Chemical-based farming is commonly used with hybrid plants, which are more susceptible to pests and blights. Golden flax is rarely if ever organically-grown."


So, as you can see, the difference in these percentages is minor when compared to the bigger and total picture of a healthy diet.

In regard to storage,

"Storage effects: Flaxseed, either whole or coarsely ground, appears stable to long-term storage at room temperature. Even after 308 days at 22°C (72°F) there was essentially no change in peroxide value as a measure of oxidation by-products or in the percentage of ALA in fat extracted from the stored flaxseed samples5. This demonstration of oxidative stability in common storage was later confirmed by direct measurement of oxygen consumption. One gram samples of whole flaxseed, milled flaxseed and extracted flax oil were held in individual sealed glass tubes for 280 days at room temperature with 12h alternating dark/light cycles. All three preparations showed little change in headspace oxygen during this time although the flax oil sample was more variable. The fatty acid composition of all three samples remained unchanged, suggesting that flaxseed ALA was stable to both heat and light (1).

These stability results with small samples have been corroborated by studies on l kg lots of milled flaxseed which were stored in closed packages at 23°C for 128 days. The samples were examined initially and at approximately thirty-day intervals. The packages were triple-layer paper bags with plastic liners, much like those used in the 60 lb. bags normally supplied to commercial bakers. Sensory tests by a trained panel showed no difference in the aroma intensity of water slurries of fresh and stored samples at any of the four storage intervals. Changes in chemical indices of oxidation (peroxide values, free fatty acids and volatile compounds) were negligible (2). As further evidence of flaxseed’s storage stability, 36 consumers could not tell the difference between the taste of yeast breads baked with the either fresh or stored milled flaxseed included as 11% of flour weight in the recipe (3).

1. Chen Z-Y, et al. J Am Oil Chem Soc. 1992; 71:629-632.
2. Malcolmson LJ, et al. Proc Flax Inst. 1998; 57:75-80.
3. Malcolmson LJ, et al. Flax Council of Canada, Internal Report, 1997, 15pp.

This is not something that anyone needs to lose much sleep over. Buy the whole seed and grind them yourselves. Or, buy the pre-ground seed. Either way, once ground, keep in the refrigerator and they will keep for several month.

Personally, I buy the pre-ground brown flax seed and keep them stored in the fridge.

In Health
Jeff