Catching the Omega-3 Wave

Recent news items have characterized omega-3 fatty acids, and foods that contain them, as superfoods or wonder-foods, or some such magic elixir of life. While the hype sometimes goes overboard, a growing collection of solid science gives credence to the concept that a generous dietary dose of omega-3s will provide a host of benefits, throwing open the door to increasing opportunities for new-product development. But keeping this trend on course requires a body of sound research confirming the range of benefits and the development of more ingredients and products that meet manufacturers needs and please consumers taste buds.

The biochemical angle 

Typical dietary sources of omega-3 fatty acids include fatty marine fish and shellfish, and several plant and nut oils. Fish oil contains the long-chain fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while English walnut, canola, soybean, flaxseed and olive oil contain the shorter-chain alpha-linolenic acid (ALA).

Fish obtain omega-3s by consuming marine algae and phytoplankton.

Fatty cold-water fish, such as mackerel, herring, tuna, salmon, sardines and trout, have the highest levels, although leaner cod or haddock also provide smaller amounts. The omega-3 levels also vary within the species.

Long-chain omega-3s produced from a wild fish source will contain small variations of omegas, due to water temperature, quality and quantity of natural food source, and harvest location and time of year, says Hope Hale, senior marketing manager, OmegaPure, Omega Protein, Inc., Houston. The total long-chain omega-3 content range is from 28% to 32% by volume. The EPA to DHA ratio is typically 1:1, and the fatty-acid profile contains a minimum 10% EPA and 10% DHA. The processes used to manufacture refined fish oil include standardization for food and beverage fortification purposes.

When we refer to omega-3s in foods, we generally mean DHA, EPA and ALA. These polyunsaturated fatty acids have their first double bond at the third carbon molecule from the methyl (CH3) end of the fatty acid, hence the name omega-3 (n-3). However, typically these are separated into two groups based on their structure and nutritional function: DHA (22:6n-3) and EPA (20:5n-3) are considered long-chain polyunsaturated fatty acids (lcPUFAs), which the body uses directly or can convert or retroconvert to the other lc form as needed, and shorter-chain ALA (18:3n-3), which the body cannot synthesize so its often termed an essential fatty acidbut can transform into the needed lc forms. The conversion rate is modest (generally considered to be less than 1% to about 5%, and is influenced by sex and age and the consumption of competing fatty acids, such as linoleic acid and the omega-3 lcPUFAs). According to 2005 Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) from the National Academy of Sciences/ Institute of Medicines Food and Nutrition Board, Because the physiological potency of EPA and DHA is much greater than that for á-linolenic acid, it is not possible to estimate one AMDR (Acceptable Macronutrient Distribution Range) for all n-3 fatty acids. Approximately 10% of the AMDR can be consumed as EPA and/or DHA.

In addition to the three common omega-3s, stearadonic acid (SDA, 18:4n-3) occurs naturally in echium, black-currant oils and certain other plants. Some researchers consider it a pro-EPA compound with better conversion in the lcPUFA synthesis in mammals. SDA is an intermediate step in the process, resulting from desaturation of ALA. However, in humans and most animals, it doesnt accumulate, says Joyce Nettleton, D.Sc., R.D., spokesperson for the Alaska Seafood Marketing Institute, Juneau, and editor, PUFA Newsletter, Denver. Its important, however, because it uses the same enzyme that converts the equivalent omega-6s, linoleic acid to gamma-linoleic acid, and that is the most-limiting step in the conversion of ALA to the long-chain forms. Because the human body skips that stepthe plant does the conversionconsuming SDA should prove beneficial in creating lcPUFA omega- 3s in the body.

Hooked to heart health 

The most widely known and accepted benefit of omega-3 fatty-acid consumption is its link to improved cardiovascular health. There remains much to be learned about the role of omega-3 in heart health, says Nettleton. But, what is clear and beyond dispute is the data from fish-eating populations.

Researchers first observed the effect in Greenlands Inuits, who exhibited a low rate of heart disease compared to the general population. Researchers believed this resulted from the groups traditional diet, comprised largely of marine animals and fish with high levels of EPA and DHA, but low levels of linolenic acid (LA). More and larger studies mirrored these findings, showing that increased omega-3 consumption lowers triglycerides; reduces the risk of heart attacks, abnormal heart rhythms and strokes in people with cardiovascular disease; and reduces atherosclerotic plaques, or hardening of the arteries.

These studies led FDA to approve a qualified health claim for reduced risk of coronary heart disease (CHD) on conventional foods that contain EPA and DHA: Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease. One serving of [name of food] provides [x] grams of EPA and DHA omega-3 fatty acids. [See nutrition information for total fat, saturated fat and cholesterol content.]

The actual amount required is currently under investigation. In general, studies suggest that taking levels of combined EPA and DHA ranging from 0.5 to 1.8 grams per day can significantly reduce death from heart disease and all causes. For ALA, a total intake of 1.5 to 3 grams per day appears to produce health benefits.

Casting a wider (health) net 

Perhaps just as potentially significant as its relation to heart health is omega-3s role in, and effect on, other aspects of human health. Scientific studies showing similar conclusions lead to scientific agreement and health recommendations, observes Hale. Many of these are rooted in omega-3s participation in anti-inflammatory and neurological functions.

DHA is involved in the relay of neurological signals within the cell and between cells, says Nettleton. DHA is a requisite polyunsaturated fatty acid in every brain cell membrane, and it is the predominant fatty acid in brain cell neurons. It has been shown that the brains of infants of mothers who didnt breastfeed at all, or for very long, had less DHA than those who were breastfed.

Research also shows that omega-3 lcPUFAs in fish oils (approximately 18% EPA and 12% DHA) can produce anti-inflammatory effects at daily doses of 3 to 6 grams (PUFA Newsletter, Dec. 2006).

Behavior and cognitive function are garnering much attention, says Doreen VandenTillaart, vice president, administration, Natunola Health, Ottawa. There is ongoing research to suggest that omega-3 may help brain function and be useful in the treatment of ADD and ADHD related symptoms, she says.

However, Nettleton observes, We dont know enough about how specific areas of the brain operate. In the areas of behavior and psychosocial development, she notes, links are much harder to establish and its hard to reliably measure subtle changes in behavior. The two areas showing promise, she says, are Alzheimers disease and immune inflammatory response in the brain and other tissues.

These potential benefits require additional research before FDA would be inclined to allow anything beyond a structure/function claim on the labels of conventional foods and beverages. For example, according to Linda Pizzey, CEO, Pizzeys Milling, Angusville, Manitoba: Products containing ALA omega-3 from flaxseed qualify for structure/ function claims such as ALA omega-3 supports cardiovascular health and ALA omega-3 supports general health.

Fishing for new sources 

Although many health professionals recommend fish for an omega-3 lcPUFA fix, many Americans dont put seafood at the top of their shopping lists. Add general supply and price issues, lack of oxidative stability, and environmental and contamination issues (depletion of fish stock and contaminants such as mercury), and you have the impetus for improving existing products and developing entirely new sources.

Fish-oil derived products are a popular way to incorporate omega-3s, but stability and off flavors are always the biggest hurdles to overcome. Fish taste fishy for a reasonthey are prone to oxidation. Omega-3s, as with all unsaturated fats, should be handled with care to prevent oxidation and reduced sensory quality, says Bruce Artman, director, applications development, Martek Biosciences, Columbia, MD. Typically, we recommend limited exposure to air, elevated temperatures, contact with transition metals and exposure to light. These are typical initiators of oxidation and should be considered when using any form of unsaturated fats.

Of course, the oil needs to start out with high quality: refined to remove free fatty acids; bleached and deodorized to remove contaminants; and steam deodorized to ensure that it is not degraded. Additionally, new ingredients and technologies can minimize the negative effects. The most promising is micro-encapsulation, a process that surrounds small droplets of oil with a protective matrix, usually proteins and/or carbohydrates. This not only protects the oil from oxygen exposure, but, depending on the encapsulating material and process, can protect the taste buds from the oil. The oil content of spray-dried ingredients is usually 20% to 35%. Coacervation techniques can deliver about 50% to 80% oil and can provide more flexibility in the encapsulating material and its application. To improve stability, antioxidants can be added to either the oil or the shell material.

But for those who want to steer clear of fish, many other sources exist. Microalgae, such as Crypthecodinium cohnii and Schizochytrium, produce copious amounts of DHA. lifesDHA, derived from a vegetarian sourcealgaeis ideal for food and beverage applications, says Artman. Because it is derived from algae grown outside of the ocean and not from fish, it will not pose the same sensory and formulation challenges that have been associated with fish oil.

While the microalgae-derived products are vegetarian, some consumers feel more comfortable with ingredients from the field or orchard. Rich sources of ALA include walnuts (9%), standard soy and canola oils (8% and 11% of the oil, respectively) and flaxseed (57% of the oil).

As flaxseed is a natural vegetable source of omega-3 with a pleasant taste, flaxseed-enriched foods are driving this omega-3 trend, according to VandenTillaart. Additionally, as incorporating flaxseed into current formulations is a simple and inexpensive process, she says, I believe this demand will rapidly increase as the sales for omega-3-enriched consumer products continue to grow.

Flaxs hull limits digestibility, so often ground flax is used in food products. This, however, makes it more susceptible to oxidation, due to its high level of unsaturated fatty acids, so Natunola developed a patented shelled product that has a six-month shelf life without refrigeration. VandenTillaart points out that 5 grams of the companys product provides 1.5 grams of omega-3; therefore, only a small amount of Natunolas shelled flax is required to obtain the daily recommended intake.

Flaxseed naturally contains between 18% to 24% ALA, says Pizzey. However, growing conditions can affect levels. We have found that warmer growing seasons, for example, flaxseed grown in the northern U.S. vs. the Canadian prairies, she says, will often yield flaxseed that is lower in ALA content.

Flax is also the origin of some enhanced animal products, especially omega-3 eggs, which are gaining favor with the consumer. Feeds with safflower oil, perilla oils, chia, marine algae and fish can also increase the omega-3 content of egg yolk.

Those looking for more-exotic sources of ALA might try oils from the following: black currant, borage, chia, cranberry, hemp, perilla, purslane and pumpkin. Several products have been commercialized, although some have not received GRAS status and are limited to use in supplements.

Chia is used as a generic term for Salvia species, but Salvia hispanica oil contains significant levels of ALA; chia extract has more than 600 mg omega-3s per 1.0 gram of extract.

The primary key to the stability of Tresalbio Salvia hispanica, or chia, seed extract vs. other plant-based forms of omega-3s is the natural material itself, says Sid Hulse, vice president, marketing and sales, Valensa International, Eustis, FL. Basically, chia has a very high level of naturally occurring tocopherols that help prevent peroxidation. A CO2 extraction process increases stability, contributing to longer shelf life and reduced rancidity.

Cranberry seeds are a byproduct of processing cranberries into juice and juice-derived products. The oil can be processed through supercritical fluid extraction in an oxygen-free atmosphere, which eliminates oxidative degradation. Hulse says the omega-3 content of his companys cranberry seed extract is approximately 30% to 35% and has a very mild, grassy flavor, and it is virtually odorless.

Biotechnology may also bring enhanced omega-3 oilseeds. Monsanto, St. Louis, is working with canola to develop a source of SDA. In addition, Monsanto and The Solae Company, St. Louis, who have been independently conducting research on soybeans, have joined forces to develop a highomega- 3 strain of soybean. Soybeans represent a renewable, land-based source of omega-3s, says Jerry Steiner, executive vice president, Monsanto. We believe this collaboration will allow us to bring to market a variety of sustainable omega-3 ingredients that will nutritionally enhance foods that consumers already enjoy.

Taking the fortification plunge 

Consuming DHA in foods is an easier, more enjoyable way to do something good for your body, says Artman. It also provides an easy way to incorporate DHA into childrens diets.

According to a recent market research report, Omega-3 Fatty Acids and the U.S. Food and Beverage Market, published by Packaged Facts, Rockville, MD, foods and drinks enhanced with omega-3 fatty acids will grow from $2 billion in 2006 to $7 billion by 2011. You can currently find a range of omega-3 foods on the market, including grain products and dairy products, with grain products dominating the market, says Artman. However, he notes, most of these contain ALA, an omega-3 precursor for DHA that is inefficiently converted by the body into DHA in small amounts. However, experts predict that the dairy segment will continue to grow and may capture the market with products like enhanced yogurts, milks, ice creams and cheeses. He notes that Marteks DHA ingredient remains stable when subject to thermal processing conditions such as pasteurization (UHT, HTST and batch), baking, cooking, retorting, extruding, drying (tunnel, spray, drum, etc.), freeze drying, refrigeration, freezing, mixing and/or high shear and fermenting.

When formulating with omega-3s, one of the first considerations is the fortification level. Target delivery levels for long-chain omega-3s EPA and DHA vary depending on the food matrix, serving size and storage conditions, says Hale. Generally, fortification levels can range from 32 mg to 100-plus mg per serving. Refrigerated, frozen and short-shelf-life foods are best suited for omega-3 incorporation. Products that contain fat assist in omega-3 incorporation, due to the synergism of the oils and resultant increase in oxidation protection.

When making a product containing fish oil, replacing a portion of the existing fat with omega-3 oil and blending them together produces good results. For example, if a formula calls for 2% canola oil, you would replace a small portion of the canola oil with fish oil, based on target delivery levels, explains Hale. The total fat level would remain the sameat 2%but the fat would now be a blend of fish and canola oil. This mixing of oils provides additional thermal stability to the fish oil during processing. She cautions that adding omega-3s to a formula will sometimes mute flavors, but increasing the amount of flavoring can compensate for this. Emulsifiers can be used in combination with the oil in a system that has little or no fat.

One interesting concept is adding flaxseed to a smoothie-type beverage, says Pizzey: Flaxseed imparts a mild, nuttyoatmeal like flavor, which works very well in milk, soy and even fruit-based beverages.

For all omega-3 applications, protection from oxygen is critical. Antioxidants can be added based on the food being fortified. Products can be packaged similar to their nonfortified counterparts, but oxygen scavengers, nitrogen blanketing and opaque packaging can provide additional protection. 

Fish Contaminants

Before panicking about contaminants in fish and fish oil, keep in mind two facts: A recent analysis of existing research (JAMA, Feb. 14, 2007; 297(6):585) concluded: For major health outcomes among adults, based on both the strength of the evidence and the potential magnitudes of effect, the benefits of fish intake exceed the potential risks. For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.

While studies have shown that some species of fish may be high in mercury, says Hope Hale, senior marketing manager, OmegaPure, Omega Protein, Inc., Houston, highly refined fish oil provides a safe source of omega-3s for human consumption, as heavy metals, including mercury, have been removed during refining. Food and beverage products developed with refined fish oil provide a pure and safe dietary source of EPA and DHA. 

Making the Grade

The National Institutes of Health compiled a list of potential uses of omega-3s based on scientific evidence and graded them from A (high) to D (low) based on strength of evidence. Various coronary heart disease benefits were discussed: Hypertriglyceridemia and secondary cardiovascular-disease prevention were rated A; primary cardiovascular- disease prevention was rated B; angina pectoris, atherosclerosis and cardiac arrhythmias received a C. Primary and secondary cardiovascular-disease prevention by ALA also received a C. The following also were reviewed and graded: