Monsanto reports safety of SDA-rich soybean oil

Scientists for the biotech giant have published results of a 90-day feeding study in rats with its SDA soybean oil, which reported no adverse effects and concluded that he SDA soybean oil was safe for human consumption.

SDA is an intermediate omega-3 fatty acid in the conversion of alpha-linolenic acid (ALA), an omega-3 found in plants, into eicosapentaenoic acid (EPA), the long-chain omega-3 found in fish. Human conversion of ALA to EPA is relatively small.

Ben Kampelman, public affairs manager for Monsanto told NutraIngredients.com that the GM soybeans are not yet commercially available, but they are in the advance development phase.

“This is the third phase, and following this phase is the fourth and final step in the process, which we call pre-launch,”​ he said.

“We expect that the product will be commercially available after the turn of the decade.”​

A competitive field​

Other industry giants are active in the engineering of plants to contain the longer chain omega-3 fatty acids EPA and docosahexaenoic acid (DHA) obtained principally from marine sources or algae.

Indeed, 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 (see related article​).

DuPont is also active in the production of EPA-producing plants, and has reportedly working on EPA-producing soybeans. Indeed, Anthony Kinney from Dupont told attendees at the 17th International Symposium on Plant Lipids in 2006 that the company has achieved "target long-chain PUFA contents up to 40 weight per cent of the oil of homozygous soybean seeds."​

Engineering plants to produce EPA and DHA presents additional challenges to plant scientists. SDA is an intermediate between the plant-based omega-3 alpha-linolenic acid (ALA) and EPA. Some vegetable oils already contain significant quantities of SDA, such as echium oil and borage oil. Indeed, Croda recently received novel foods approval in Europe for its SDA-rich echium oil called Incromega V3.

Engineer to SDA or EPA?​

The Monsanto scientists transferred genes into soybean plants for delta-6 and delta-15 desaturase enzymes, which convert linoleic acid (LA) and ALA in soybean oil to SDA. ​

“The stability, taste and processing of the soybean are key reasons to stop at SDA. Oils which are closer to fish oil are less stable, impart a fishy taste, and require special handling to maintain product quality,” ​said Kampelman. “EPA or DHA is highly complex and may take many more years to come to market.”​

Kampelman said that the company’s product concept is to deliver a consistent 20 per cent SDA in soybean oil. This could be produced by blending if necessary, he said.

SDA is an intermediate in the production of EPA, and, according to Kampelman, SDA is between 17 and 33 per cent as effective as EPA at raising EPA levels in cell membranes. He added that it is not known, however, how much EPA is burned for energy versus how much is retained as EPA in cell membranes.

Commercial value​

Kampelman indicated that the SDA soybean could improve compliance to the consumption of omega-3 “via the delivery of food products which simply could never exist using marine oils due to their poor stability and flavor characteristics”.

“Because SDA has improved stability and flavor characteristics and because it can be readily produced in large quantities, SDA soybean oil will allow the delivery of omega-3 benefits to consumers through a wide variety of products and uses,”​ he said.

The oil would be used primarily as a food ingredient, added Kampelman. “We have been able to demonstrate across a wide range of foods that incorporation of SDA maintains flavor quality, shelf life and is well liked by consumers,” he said. ​

“While SDA itself could be used as a dietary supplement, the real advantage of SDA over marine oils (aside from cost) is the fact that SDA can be incorporated into many existing foods without losing consumer acceptance.”​

Safety data​

In this month’s issue of Regulatory Toxicology and Pharmacology​, Monsanto’s Bruce Hammond and co-workers report results from their toxicology studies in rats with the SDA soybean oil.

A 28-day pilot study showed no “treatment-related adverse effects”​, wrote the researchers. This was followed by a 90-day/one generation rat reproduction study that, again, reportedly showed no adverse effects when consumed at doses of 1.5 and 4 grams per kilogram of body weight.

Source: Regulatory Toxicology and Pharmacology​ ​December 2008, Volume 52, Issue 3, Pages 311-323"Safety assessment of SDA soybean oil: Results of a 28-day gavage study and a 90-day/one generation reproduction feeding study in rats"​ ​Authors: B.G. Hammond, J.K. Lemen, G. Ahmed, K.D. Miller, J. Kirkpatrick, T. Fleeman