Many new and novel PUFA sources are riding the wave of popularity created by omega-3 fatty acids from fish. Mark J Tallon, PhD, assesses the landscape
Whilst the popular press is still caught up in the 'fats are fatal' trend, the marine and nutraceutical industries are more aware than ever of the beneficial influence of healthy fatty acids.1 Consumer awareness of health-promoting fatty acids has jumped dramatically, spearheaded by ad campaigns by groups such as Ocean Nutrition and Martek Biosciences. Recent figures suggest that nine per cent of dietary-supplement consumers realise that some fatty acids are beneficial for health, with the greatest awareness regarding polyunsaturated fatty acids (PUFAs) such as omega-3s.1
However, new fatty acid extraction sources have emerged to take a bite from the $190 million pie, including hemp, cranberry, pomegranate, microalgae and blackcurrant seed oils. Let's take a closer look at the latest research filtering down to boost public confidence regarding the beneficial effects of fatty acids in 2006.
Language — that essential part of communication — is intricately influenced during our early years of development. The omega-3 docosahexaenoic acid (DHA) accumulates in the brain during the first and second years of life.2 One study aimed to see if an increased content of DHA in breast milk via maternal fish oil supplementation affects mental development in term infants.3 A total of 122 Danish mothers with a habitual fish intake below the population median were randomised to 4.5g/day of fish oil or olive oil for the first four months of lactation. Fifty-three mothers with habitual fish intake in the highest quartile were included as reference group. The effect of increasing infant DHA intake and serum DHA levels were assessed on infant problem-solving ability at nine months and language at one and two years of age.3
Infants in the three groups performed equally well on the problem test and no association was observed between problem solving and erythrocyte-DHA at four months. Passive vocabulary at one year was lower in the children of the fish oil compared with the olive oil group, but no differences were found at two years of age. Word comprehension at one year was inversely associated with erythrocyte-DHA at four months. This trial identifies just some of the potential benefits of DHA levels in breast milk on early language development of breast-fed infants.3
Acute epilepsy treatment
With more than 2.7 million Americans living with epilepsy, any treatment strategies without side effects are warmly welcomed. Research from preliminary clinical observations in animal studies suggest nutritional supplementation with omega-3 fatty acids may be useful in the non-pharmacological treatment of patients with epilepsy.4 Omega-3s increase seizure thresholds and lower inflammatory mediators, which increase in patients with epilepsy.4
Researchers from University College London's Institute of Neurology carried out a randomised, double-blind, placebo-controlled, parallel group trial of omega-3 supplementation on 57 patients with 1g/day eicosapentaenoic acid (EPA) and 0.7g/day DHA for 12 weeks.5 Seizure frequency was reduced over the first six weeks of treatment in the supplement group, but this effect was not sustained. The supplementation produced a significant increase in EPA and DHA concentrations and a reciprocal fall in arachidonic and linoleic acid concentrations.5
Although a great start in the natural treatment of human epilepsy, further studies are required to examine different omega-3 preparations, different doses, longer treatment durations and larger sample sizes.
Cardioprotection: Black currant and virgin oils
According to the American Heart Association, in 2004, there were 61.8 million cases of cardiovascular disease in the US. As part of the work to decrease these numbers, researchers investigated novel forms of fatty acids in 15 healthy females. Subjects participated in a randomised, double-blind, crossover study including two four-week periods with either 3g/day of black currant seed oil or 2.8g/day of fish oil separated by a four-week washout period.6 The results show that black currant seed oil supplementation increased the proportion of 18:3n6 in triacylglycerols (TAG) and cholesteryl esters (CE), and that of dihomo-gamma-linolenic (20:3n6) in TAGs, CEs and glycerophospholipids (GPLs).
Proportion of 18:3n6 was higher after black currant seed oil than after fish oil in TAGs and CEs, as well as that of 20:3n6 in TAGs, CEs and GPLs. Serum levels of LDL cholesterol were lower after black currant seed oil compared to fish oil.6 These results suggest other sources of beneficial oils are bioavailable outside of traditional fish oil sources.
As a direct treatment and preventive intervention, dietary supplementation with virgin olive oil is considered cardioprotective. Decreasing LDL and apolipoprotein (apo) AII-lipoproteins is also appropriate for coronary heart disease protection and treatment.7 One study assessed the effects of an eight per cent energy dietary exchange of linoleic acid for oleic acid on serum and lipoprotein levels and serum and LDL-TBARS (thiobarbituric acid reactive substances) in postmenopausal women consuming a diet rich in fat (46% En; saturated/monounsaturated/polyunsaturated profile: 1.1/1.9/1).8 Fourteen postmenopausal women were assigned to exchange during a 28-day dietary period the culinary oil used for years consisting of a blend of olive oil plus sunflower oil (SO) for extra-virgin olive oil (EVOO). SO and EVOO represented 62 per cent of the total lipid intake.
Dietary intakes, serum Lp(a), and cholesterol, triglycerides, phospholipids, protein and apolipoproteins AI, AII and B were determined in serum and lipoproteins. The dietary intervention decreased serum total cholesterol, phospholipids, apo AII and apo B. Except for triglycerides, all components of the LDL fraction decreased. HDL cholesterol was not affected but HDL phospholipids and HDL lipids decreased. Furthermore, the estimate of 10-year cardiovascular risk decreased. These findings offer some new insight to the food market regarding oil compositions and suggest that a dietary exchange of an olive oil and sunflower oil blend for extra virgin olive oil is beneficial based on decreases in LDL, apo AII levels and an estimate of 10-year cardiovascular risk.
CLA and Inflammation
Conjugated linoleic acid (CLA), more famous for fat loss,9 has also been shown to increase 15-keto-dihydro-prostaglandin F2alpha, a marker for cyclooxygenase-mediated lipid peroxidation and thus an indicator of cyclooxygenase-mediated inflammation.10
Researchers from Sweden investigated the effects of CLA on other indicators of inflammation in human subjects, including C-reactive protein, TNF-alpha, TNF-alpha receptors 1 and 2, and vascular cell adhesion molecule-1.11 In a double-blind, placebo-controlled study, 53 human subjects were supplemented with a mixture (4.2g/day) of the isomers cis-9, trans-11 CLA and trans-10,cis-12 CLA or control oil for three months. CLA supplementation increased levels of C-reactive protein compared with the control group. However, no changes in TNF-alpha, TNF-alpha receptors 1 and 2, and vascular cell adhesion molecule-1 were detected.
This data may suggest CLA increases inflammation based on C-reactive protein changes. However, because C-reactive protein is sensitive to other low-grade inflammatory infections, more data is needed to assess if the GRAS-approved ingredient influences inflammatory-based disease states over the long term.
Skin and Hempseed
With hemp food sales approaching $4.6 million in 2005, research behind its beneficial effects on health is becoming more desired for mainstream marketing. Hempseed oil is a rich and balanced source of omega-6 and omega-3 polyunsaturated fatty acids (PUFAs) providing possible opportunities in disease treatment from CVD to skin care.
Dietary hempseed oil and olive oil were compared in a 20-week randomised, single-blind, crossover study with atopic patients. Fatty acid profiles were measured in plasma triglyceride, cholesteryl and phospholipid fractions. A patient questionnaire provided additional information on skin dryness, itchiness and usage of dermal medications.
Levels of linoleic acid (18:2n6), alpha-linolenic acid (18:3n3) and gamma-linolenic acid (GLA; 18:3n6) increased in all lipid fractions after hempseed oil, with no significant increases of arachidonic acid (20:4n6) in any lipid fractions after either oil. Finally, qualities of both skin dryness and itchiness improved and dermal medication usage decreased after hempseed oil intervention.
This evidence suggests that not only does hempseed oil cause significant changes in plasma fatty acid profiles but also improved clinical symptoms of atopic dermatitis. These improvements may be a direct result of abundant supply of PUFAs in this hempseed oil or one of its lesser-known bioactives.
As mentioned earlier, European diets provide a suboptimal intake of eicosapentaenoic (20:5n3) and docosahexaenoic (22:6n3) acids, which are derived mainly from fish oils.12 A recent study indicates that the supplementation of black currant seed oil, which contains 14.5% alpha-linolenic (18:3n3), 12.6% gamma-linolenic (18:3n6), 47.5% linoleic (18:2n6) and 2.7% stearidonic (18:4n3) acids, could potentially serve as alternative to fish oil as an n-3 fatty acid source.13
Studies such as this novel intervention trial highlight the strength and buoyancy of the fatty acid market. Pomegranate oils show cancer-fighting properties.14 Blending healthy oils ameliorate the decreased blood omega-3 fatty acid levels associated with Attention Deficit Hyperactivity Disorder.15 As breakthrough technologies surface this market is set to move from strength to strength, expanding its global grip for the foreseeable future.
1. No Author. Cogent Research: Consumer views on functional foods. 2002 (March). International Food Information Council. Cambridge, Massachusetts USA.
2. Cunnane SC, et al. Breast-fed infants achieve a higher rate of brain and whole body docosahexaenoate accumulation than formula-fed infants not consuming dietary docosahexaenoate. Lipids 2000;35(1):105-11.
3. Lauritzen L, et al. Maternal fish oil supplementation in lactation: effect on developmental outcome in breast-fed infants. Reprod Nutr Dev 2005;45(5):535-47.
4. Schlanger S, et al. Diet enriched with omega-3 fatty acids alleviates convulsion symptoms in epilepsy patients. Epilepsia 2002;43(1):103-4.
5. Yuen AW, et al. Omega-3 fatty acid supplementation in patients with chronic epilepsy: a randomized trial. Epilepsy Behav 2005;7(2):253-8.
6. Tahvonen RL, et al. Black currant seed oil and fish oil supplements differ in their effects on fatty acid profiles of plasma lipids, and concentrations of serum total and lipoprotein lipids, plasma glucose and insulin. J Nutr Biochem 2005;16(6):353-9.
7. Rader DJ, et al. Increased production of apolipoprotein A-I associated with elevated plasma levels of high-density lipoproteins, apolipoprotein A-I, and lipoprotein A-I in a patient with familial hyperalphalipoproteinemia. Metabolism 1993;42(11):1429-34.
8. Rodenas S, et al. Dietary exchange of an olive oil and sunflower oil blend for extra virgin olive oil decreases the estimate cardiovascular risk and LDL and apolipoprotein AII concentrations in postmenopausal women. J Am Coll Nutr 2005;24(5):361-9.
9. Stangl GI. Conjugated linoleic acids exhibit a strong fat-to-lean partitioning effect, reduce serum VLDL lipids and redistribute tissue lipids in food-restricted rats. J Nutr 2000;130(5):1140-6.
10. Helmersson J, et al. Association of type 2 diabetes with cyclooxygenase-mediated inflammation and oxidative stress in an elderly population. Circulation 2004;109(14):1729-34.
11. Smedman A, et al. Conjugated linoleic acid increased C-reactive protein in human subjects. Br J Nutr 2005;94(5):791-5.
12. Sanders T. Polyunsaturated fatty acids in the food chain in Europe. Am J Clin Nut 2000;71;S176-S178.
13. Callaway J, et al. Efficacy of dietary hempseed oil in patients with atopic dermatitis. J Dermatolog Treat 2005;16(2):87-94.
14. Lansky EP, et al. Possible synergistic prostate cancer suppression by anatomically discrete pomegranate fractions. Invest New Drugs 2005;23(1):11-20.
15. Young GS, et al. Effect of randomized supplementation with high dose olive, flax or fish oil on serum phospholipid fatty acid levels in adults with attention deficit hyperactivity disorder. Reprod Nutr Dev 2005;45(5):549-58.
Mark J Tallon, PhD, is chief science officer of OxygeniX, a London-based consultancy firm specialising in claims substantiation, product development and technical writing.
Dr Tallon is also co-founder of Cr-Technologies, a raw ingredients supplier.