Food Product Design: Health/Nutrition - February 2005 - The ABCs of Omega-3s

February 2005

The ABCs of Omega-3s

It's official: FDA is finally singing the praises of omega-3 fatty acids. In Sept. 2004, the agency approved a qualified health claim allowing any conventional food containing at least 125 mg per serving of two long-chain polyunsaturated omega-3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Foods that have these and that are low in fat, saturated fat, trans fat and cholesterol can state on the package: "Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids might reduce the risk of coronary heart disease."

The claim offers omega-3s government-sanctioned gravitas and puts FDA on the same page as many international bodies that acknowledge the nutritional might of these healthful fats. "With more than 8,000 technical papers published regarding omega-3 fatty acids, there appears to be no doubt that DHA and EPA have important metabolic functions in humans," says Herbert D. Woolf, Ph.D., technical marketing manager, BASF North America, Mount Olive, NJ.

Cashing in on the claim's cache isn't as simple as squeezing fish oil into a formula. As with any supplementation effort, product developers must approach it with due prudence: How much omega-3 do we add? Which omega-3 do we add? Where do we add it? And why do we want it there in the first place?

Something's fishy
For decades, a paradox puzzled Western physicians practicing in the Arctic: Despite diets saturated with fatty fish, whale blubber and seal meat, Inuit patients rarely developed coronary heart disease (CHD). Once researchers took a wide-angle view of these anecdotal observations, they found that heart-disease rates among Greenland's Inuits were lower than among Westerners. Why does a population that consumes roughly as much fat as is common in the West suffer fewer cases of the West's quintessential disease?

A consensus emerged that's a classic case of quality, not quantity. The Greenland rates suggested that a high-fat diet doesn't invariably lead to heart disease. What's more, epidemiological studies of other fish-eating populations, such as the Japanese, demonstrated an inverse relationship between avid fish consumption and coronary disease. Ergo, something in fish appeared to protect the heart -- something we now believe is the high concentration of long-chain omega-3 polyunsaturated fats.

The findings garnered loads of publicity, and by now, almost everyone has heard of omega-3s. In 2002, the Gallup Organization, Washington, D.C., found that awareness had reached 53% of U.S. consumers, with 33% of adults able to name at least one of the fats' health benefits. But other than knowing that "fish fats" are good for you, do consumers -- and product developers -- really know what they are and why they merit attention?

Omega-3s belong to a family of polyunsaturated fatty acids (PUFAs) whose first double bond occurs at the third carbon from the methyl end -- hence omega-3. Alpha-linolenic acid (ALA), at 18 carbons and 3 double bonds, is the parent omega-3. Because our bodies can't synthesize it -- it's "essential" -- we're obliged to obtain it via diet, mainly through flaxseed and its oil, canola oil, walnuts, and, for bottom feeders, marine algae.

Despite its own benefits, particularly for the skin and hair, ALA's main value derives from its role as a precursor to the two more biologically active omega-3s mentioned in FDA's claim: 20-carbon, 5-double-bond EPA and 22-carbon, 6-double-bond DHA. Ideally, elongase and desaturase enzymes convert ALA into these long-chain metabolites, but more than 80% of ALA goes to beta-oxidation, and conversion of the remainder is notoriously inefficient -- one 1998 study traced only 6% of ALA all the way to EPA and 3.8% to DHA. And research indicates that the body prefers preformed long-chain omega-3s over converted ALA anyway, notes Brian Langdon, manager, technical sales support, Omega Protein, Reedville, VA, making EPA and DHA, if not technically essential, at least conditionally so.

Enter coldwater fatty fish. About 30% of the fat in wild coho and Atlantic salmon, lake trout, sardines, mackerel, albacore tuna, herring, and similar species is stored as EPA and DHA. While the mechanisms by which they protect the heart are complex, multifactorial and still under study, their effects are tough to deny. Most dramatic might be their "evening out" of the arrhythmias implicated in approximately 80% of sudden cardiac deaths. And, increased intake of long-chain omega-3s can lower circulating triglyceride levels by as much as 30%, says Marianne O'Shea, nutrition and technical services manager, Lipid Nutrition, Channahon, IL.

Once converted into eicosanoids -- hormonelike substances that attenuate inflammatory disorders, such as Crohn's disease and rheumatoid arthritis -- EPA thins the blood, making it less likely to become atherosclerotic plaques and precipitate thromboses and strokes. By improving endothelial function and increasing arterial flexibility, EPA-based eicosanoids help blood flow more smoothly, too. And along with DHA, they slightly lower blood pressure in subjects with mild preexisting hypertension.   

Beyond heart health, observational studies and randomized controlled trials reveal even more benefits correlated with increased long-chain omega-3 consumption, starting with the simple maintenance of supple cell membranes. The presence of highly unsaturated DHA in retinal and neural cells allows for the speedy exchange of visual signals, neurotransmitters and cellular materials, particularly during early brain and eye development. "In the last three months of pregnancy, there is rapid accumulation of DHA in brain and nerve tissue," O'Shea says, and because about 30% of gray matter's structural lipid is DHA, it "plays a major role in the mental development of infants, as well as in the mental function of children and adults throughout life."

Angela Tsetsis, business development, Martek Biosciences Corporation, Columbia, MD, sees DHA as "bookends at the beginning and end of life, with the beginning being the critical development period for infants and the end being their role in some of the conditions that come with aging -- cardiovascular disease being one and vision conditions being another. There have been three different studies that, by looking retroactively at people's diets, have shown that those who have higher levels of DHA have fewer incidents of Alzheimer's later in life." DHA might even moderate bipolar disorder, schizophrenia, dementia, depression, alcoholism and ADHD. Although no one's established a definitive link, the results encourage further study.

Out of balance
How hard could it be to get a few hundred milligrams of EPA and DHA? Harder than it looks. Estimates vary, but average U.S. long-chain omega-3 intake hovers around 71 mg per day, landing us near the bottom in consumption worldwide.

Maybe we're not eating enough fatty fish. Then again, not everyone should: Not only does the fat contain beneficial omega-3s, it's also the collection point for environmental undesirables, such as polychlorinated biphenyls (PCBs) and dioxin. Mercury concentrations are another concern, particularly for young children and childbearing women, who should steer clear of fish with mercury levels above 1 ppm, according to the AHA.

We could get our omega-3 fatty acids from other foods and in other forms -- as vegetable-source ALA, for example. Even so, we'd still have to clear the conversion hurdle, says Michael Green, category manager, Nu-Mega Ingredients, Brisbane, Australia. "Vegetarians may actually have a higher capacity to biosynthesize EPA and DHA from ALA," he concedes, "but they're still not getting anywhere near the levels of EPA and DHA they should."

Loading foods with another polyunsaturated family that, while as essential as omega-3s, risks crowding them out of our diets: the omega-6s. Omega-6 linolenic acid (LA) appears in seeds, nuts and oils of plants such as corn, safflower, sunflower and soy -- ubiquitous in processed foods -- thus making LA the most-common polyunsaturated fatty acid in the West. "Today, the American diet has an omega-6:omega-3 ratio of 40:1 or greater," Langdon says, well above the World Health Organization's recommended 5:1 to 10:1.

Green calls this imbalance "one of the most underreported and underrated health issues of our generation." Because LA and ALA share the elongases and desaturases used to form long-chain metabolites, the oversupply of the former so out-competes the latter that ALA can hardly cobble together an EPA or DHA edgewise. Adding insult to injury, omega-3 eicosanoids are proinflammatory, "possibly facilitating the development and augmenting the symptoms of inflammatory conditions, such as psoriasis, asthma and arthritis," he adds.

The only way to tilt the ratios into more reasonable balance, Langdon says, "is to increase long-chain omega-3s in the diet through everyday food formulation, and decrease our reliance on omega-6 oils."

Infant formulas are a wise place to start. Only within the past few years have DHA-fortified formulas been on the market, Tsetsis says. While DHA-fortification isn't "life-or-death" for healthy infants, she emphasizes optimal development: "There have been meta-analyses that show that babies who get DHA and ARA (an omega-6 essential to infant development), whether through breast milk or infant formula, have at least a 3-point IQ advantage. If you look on a total-population basis with the average being 100, if the whole population bumps up 3 or 6 points, it's a big deal."

The right candidate
If raising the nation's IQ isn't reason enough to fortify, perhaps profit is. Forecasts predict U.S. functional food sales to reach $25.7 billion this year and $34.2 billion by 2010, according to Omega Protein literature. Even before the health claim, launches of DHA- and EPA-containing products rose from 14 to 45 and 6 to 32, respectively, between 2002 and 2003, per the Chicago-based Mintel Group's Global New Products Database. Concepts to consider, O'Shea suggests, include yogurt and yogurt drinks; breakfast, sport and meal-replacement bars; sausages and meat pâté; breads, cookies, cakes and crackers; UHT milk; emulsified sauces; margarine; and sterilized baby foods in jars.

Before taking the concepts public, formulators should measure how they fit with the whole enterprise of fortification. As Langdon says: "Food processors need to think: Will my normal processing conditions destroy the omega-3 in the final product? Can I accept a more-nutritious and more-desirable product at the cost of a shorter shelf life? And does it make nutritive sense to fortify my product with omega-3s, or is my product pure indulgence?"

Green agrees, noting that in Australia, as in the United States, regulations prohibit using an omega-3 for a content or structure claim "in products that are inherently unhealthy, such as those with high levels of saturated fat or trans fats." After all, a wee bit of healthful fats does not a healthful fudge cake make.

How wee are we talking about? Wee enough, says Ruben Abril, principle scientist for food and feed applications at Martek's Boulder, CO, site, that a nonfat yogurt fortified with omega-3 fats could still call itself nonfat. "The amount to achieve the dose we're looking at in that case would be 100 mg per serving," he says -- well below the 0.5 grams that would show up on the nutrition panel.

  "When we talk to food formulators, we're talking anywhere from 32 mg up," adds Tsetsis. "It depends on what makes the most sense in the application. So if they're looking for something therapeutic, then they might want to add quite a bit more," up to as much as 300 mg per serving in a nutritional bar, for instance.

Straight to the source
The more omega-3s a product contains, however, the less stable it is to oxidation. The feature that makes omega-3s so valuable -- their high degree of polyunsaturation -- also leaves them inherently prone to oxidization. Air, metal ions (particularly iron and copper), pH shifts, light, high temperatures, even certain flavors, lipase enzymes, denatured milk proteins and emulsifiers: "All these factors have the ability to oxidize the oil by disrupting the double bonds and forming pro-oxidants and byproducts, such as aldehydes, trimethylamines and ketones," Langdon says. When they form, it leaves a fishy-flavored food whose compromised omega-3s add little to its nutritional value. The best prevention is to choose the right ingredient, and tailor product formulation and processing to maintain the fat's integrity.

Suppliers have traditionally sourced omega-3s from species such as tuna, salmon, menhaden, bonito and anchovy, preferring to trawl pristine waters for surface-feeders with lighter contamination loads. Subsequent purification eliminates fishy odors and contaminants. For example, the products in Parsippany, NJ-based DSM Nutritionals' ROPUFA line are neutralized with sodium hydroxide to remove free fatty acids, pesticides and pigments; bleached with silica and carbon to eliminate peroxides and heavy metals; and further deodorized to flush out aldehydes and ketones. For added comfort, GMPs and ISO certifications ensure safe mercury levels -- below 0.1 ppm.

With vegetarianism commonplace and the long-term sustainability of fishing stocks uncertain, product developers have found algal-source omega-3s revolutionary. Martek obtains its oils from the phytoplankton Crypthecodinium cohnii. At almost 60% oil, most of it DHA, the algae are tiny, long-chain PUFA factories. But these factories are not sweatshops: Austin, TX-based Whole Foods Market and Boulder, CO-based Wild Oats accept these non-GMO ingredients onto their socially conscious shelves. Fermented under tightly controlled conditions, the algae, Tsetsis explains, "multiply just as though they were living in the sea. Then we harvest them, remove as much of the water as possible, break open the cells, separate the oil and purify it."

As of now, Martek's ingredient is available as a 35%-DHA oil. Applications in salad dressings or cheese are a snap, but clear sodas and juices are more challenging, Tsetsis says. "It needs to have some emulsification system that's part of the product." Thus, she says, the best beverages for fortification are heavier, opaque ones: smoothies, meal replacements, thicker juices and homogenized dairy drinks.

Wrapping it up
"Because algal oil is more stable and has been less processed coming into the food product," Tsetsis says, "a lot of times we can just use the oil straight, which eliminates the cost of encapsulation and some of the ingredients that might affect texture and flavor when you add an encapsulated powder instead of a fat."

Nevertheless, encapsulated omega-3s have their advantages. By spray-drying the oils into a protein-sugar matrix, processors turn them into powders -- cold water dispersible, practical in dry-mix products and easier to handle. The main payoff, however, is stabilization. Microencapsulation can slow the oxidation rate from "a matter of hours to weeks and months," Green says.

Indeed, O'Shea notes that muesli bars made with her company's encapsulated fish-oil powder were "still acceptable after eight months of storage at 65?F."

However, "not all encapsulated products are the same," Langdon says. "If there is too much surface oil in the outside of the protective barrier, it will oxidize readily and odor and flavor problems will pop up."

Because of the presence of the encapsulation matrix, a given amount of omega-3 powder will contain proportionally less omega-3 than the straight oil. "Microencapsulated powders typically have between 25% and 50% oil," says John Foley, beverage laboratory manager at BASF. Thus, when working with encapsulates, "it is usually necessary to use two to four times the amount of product than if you were to use the same type of oil directly."

National Starch Food Innovation Bridgewater, NJ, recently released a new powdered, encapsulated omega-3. This menhaden-derived product was developed through a joint venture with Omega Protein, Houston.

To serve and protect
Encapsulation isn't the only route to protecting omega-3 ingredients. Cross-linking, a variation of encapsulation, is another technology used to improve the stability of fish-oil powders in certain food matrices. Or, an antioxidant cocktail of mixed tocopherols, citric acid and metal chelators, such as EDTA, also helps during storage.

Product manufacturers often add similar antioxidant blends to their products, while closely watching other aspects of formulation and processing. For example, Langdon notes that omega-3 oils aren't suited to high-temperature frying.

Fortified products fare well during pasteurization and UHT processing, but retorting requires special care. After more than 500 days of storage, Abril says, a retorted omega-3 applesauce he developed maintained both its DHA content and flavor. The key, however, was a full flushing of oxygen from the container. A nitrogen blanket confers a similar benefit during high-shear mixing, and vacuum packaging keeps things in shape for the long haul.

Other tips: Blend omega-3s with other oils prior to addition. Include them near the end of the ingredient stream. When not working with an encapsulated omega-3, encapsulate any potential oxidizers -- including stray minerals -- instead. Using deionized and deaerated water adds another measure of safety. Finally, it goes without saying that fresh and stable ingredients make for a fresh and stable omega-3-fortified product. And in the end, isn't that what we're all fishing for anyway?    

Kimberly J. Decker, a California-based technical writer, has a B.S. in Consumer Food Science with a minor in English from the University of California, Davis. She lives in the San Francisco Bay area, where she enjoys eating and writing about food. You can reach her at kim@decker.net.

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