Results of a 90-day rat study with eicosapentaenoic acid (EPA)-rich oil produced from GM Yarrowia lipolytica yeast produced no adverse effects at doses up to 976 mg EPA per kilogram of body weight per day, according to findings published in Regulatory Toxicology and Pharmacology.

“Exposure to EPA oil produced no test substance-related effects on body weight or nutritional parameters, neurobehavioral parameters, clinical or ophthalmological observations, hematology or urinalysis parameters or microscopic pathology at any tested dose,” wrote researchers from DuPont, led by Susan MacKenzie.

“The safety profile of EPA oil was comparable to that of GRAS fish oil. These results support the use of EPA oil produced from yeast as a safe source for use in dietary supplements,” they added.

Fish oils from plants

The most common source of omega-3 in the human diet is fish, which is naturally rich in DHA (docosahexaenoic acid) and EPA, both of which have been well researched for their role in cardiovascular health.

Fears about dwindling fish stocks, however, coupled with the putative risk of pollutants from oily fish, have pushed some in academia and industry to investigate the extraction of omega-3 from alternative sources.

DHA extracted from non-GM microalgae is already on the market by Martek, as is plant-source alpha-linolenic acid (ALA), a shorter chain omega-3 that is less bioavailable for humans.

However, this has not stopped a widening of the search for alternatives. One such approach has been to utilize genetic engineering of plants to produce SDA (stearidonic acid), EPA and DHA, with biotech giants Monsanto, DuPont, and BASF reporting progress. Indeed, Monsanto teamed up with Solae in 2007 to commercialize the former’s soybean variety developed specially to be rich in SDA. The oil is being commercialized by Solae under the brand name Soymega, and GRAS status (generally recognised as safe) was attained in 2009.

On the other hand, BASF Plant Science, in collaboration with Rothamsted Research and the University of York in the UK, has inserted genes from micro-organisms such as Thallasiosira pseudonana into rapeseed to produce EPA-containing vegetable oil.

The new study shows the progress of DuPont in this field, as it moves to establish the safety of its EPA-rich oil from yeast. MacKenzie and her co-workers administered doses of EPA-rich oil ranging from 98 to 976 milligrams of EPA per kg per day, or GRAS fish oil to rats for 90 days.

No effects were observed at the low doses, but at medium (488 mg EPA/kg/day) and high (976 mg EPA/kg/day) doses a reduction in total and non-HDL cholesterol levels was observed. A temporary and early reduction in HDL levels was also observed at the high dose EPA, but this was not maintained throughout 90 days, said the researchers.

“Exposure to EPA oil for 90 days produced no effects at 98 mg EPA/kg/day and no adverse effects at doses up to 976 mg EPA/kg/day,” report MacKenzie and her co-workers.

“All effects observed in the High EPA dose group were qualitatively and quantitatively comparable to those observed in the group exposed to a fish oil generally recognized as safe by the US FDA,” they added.

Branding and labelling have the most impact on consumers’ buying decisions, followed by blind tasting, concludes a study that used wine tasting as a model to determine the relative influence of different cues on purchasing intent.

When a consumer is making up their mind whether or not to buy a product they are not guided by its taste alone. A number of extrinsic factors also vie for their attention, such as awareness of the brand, labelling, price and origin. For a marketers, it is vital to understand how the different triggers that can lead target consumers towards the check out.

Authors of the new study Simone Mueller and Gergely Szolnoki said that little is know about the relative impact of the various extrinsic cues on informed product evaluation. They set out to investigate this, and how strongly consumers differ in their responsiveness. Their findings could help marketers develop more targeted strategies for product launches.

For the study, which has been accepted for publication in the journal Food Quality and Preference, Mueller and Sziolnoki recruited 521 wine drinkers in three German cities. The participants first ranked their liking of white wines in a blind tasting, then evaluated different elements of product: region of origin, grape variety, brand, and packaging style.

Wine was chosen as a good model because there is a keen interplay between intrinsic sensory characteristics and extrinsic attributes.

Overall label style and brand evaluation were seen to be the most important elements, followed by liking in the blind tests.

However not all consumer groups responded to the cues in the same way.

Younger consumers, deemed to be less experienced, used a mix of cues, whereas consumers more experienced with drinking wine tended to base their decisions on grape variety and liking.

The oldest consumers tended to be most swayed by brand and packaging. The researchers suggest that this may have been because they have had longer to form evaluation heuristics.

Price matters

The researchers introduced the issue of price only after the tasting and other cues had been evaluated. They found that product quality and taste preferences swayed purchase intent on one hand, economic constraints on the other.

The model might be applied to other products.

Mueller and Szolnoki concluded: “Our approach could be useful for products with less sensory fatigue for which a larger number of samples can be evaluated in blind and informed conditions, also reducing the potential bias from presenting identical stimuli.

“A larger test design also reduces the risk that respondents might become aware of the manipulation of evaluating the same sensory stimulus in different informed conditions.”

Some drawbacks to the design were also flagged.

“Although we aimed to include a large number of the most important extrinsic wine attributes into the experimental design, the relative effect of other cues such as closure, health claims or alcohol level still has to be explored in future research.”

Individuals whose diet includes more salad dressing, nuts, fish, poultry and certain fruits and vegetables and fewer high-fat dairy products, red meats, organ meats and butter appear less likely to develop Alzheimer’s disease, according to a report posted online that will appear in the June print issue of Archives of Neurology, one of the JAMA/Archives journals.

“Epidemiological evidence linking diet, one of the most important modifiable environmental factors, and risk of Alzheimer’s disease is rapidly increasing,” the authors write as background information in the article. “However, current literature regarding the impact of individual nutrients or food items on Alzheimer’s disease risk is inconsistent, partly because humans eat meals with complex combinations of nutrients or food items that are likely to be synergistic.”

Yian Gu, Ph.D., of Columbia University Medical Center, New York, and colleagues studied 2,148 older adults (age 65 and older) without dementia living in New York. Participants provided information about their diets and were assessed for the development of dementia every 1.5 years for an average of four years. Several dietary patterns were identified with varying levels of seven nutrients previously shown to be associated with Alzheimer’s disease risk: saturated fatty acids, monounsaturated fatty acids, omega-3 fatty acids, omega-6 fatty acids, vitamin E, vitamin B12 and folate.

During the follow-up, 253 individuals developed Alzheimer’s disease. One dietary pattern was significantly associated with a reduced risk of the disease. This pattern involved high intakes of salad dressing, nuts, fish, tomatoes, poultry, fruits and cruciferous and dark and green leafy vegetables and low intakes of high-fat dairy, red meat, organ meat and butter.

The combination of nutrients in the low-risk dietary pattern reflect multiple pathways in the development of Alzheimer’s disease, the authors note. “For example, vitamin B12 and folate are homocysteine-related vitamins that may have an impact on Alzheimer’s disease via their ability of reducing circulating homocysteine levels, vitamin E might prevent Alzheimer’s disease via its strong antioxidant effect and fatty acids may be related to dementia and cognitive function through atherosclerosis, thrombosis or inflammation via an effect on brain development and membrane functioning or via accumulation of beta-amyloid,” they write.

“Our findings provide support for further exploration of food combination-based dietary behavior for the prevention of this important public health problem,” they conclude.