August 01, 2006
Omega 3 Fatty Acids Cut Rat Prostate Cancer

Another reason why I'll eat salmon tonight:

Scientists used a special mouse model for hormone-sensitive prostate cancer that closely mirrors the disease in humans. Researchers fed one group of mice a diet comprised of 20 percent fat with a healthy one-to-one ratio of omega-6 to omega-3 fatty acids. A second group of mice were fed the same diet but with the fat derived from mostly omega-6 fatty acids.

The study showed that tumor cell growth rates decreased by 22 percent and PSA levels were 77 percent lower in the group receiving a healthier balance of fatty acids compared with the group that received predominantly omega-6 fatty acids.

The most likely mechanism for the tumor reductions, according to researchers, was due to an increase of the prostate tumor omega-3 fatty acids DHA and EPA and a lowering of the omega-6 acid known as arachidonic acid. These three fatty acids compete to be converted by cyclooxgenase enzymes (COX-1 and COX-2) into prostaglandins, which can become either pro-inflammatory and increase tumor growth, or anti-inflammatory and reduce growth.

Researchers found that pro-inflammatory prostaglandin (PGE-2) levels were 83 percent lower in tumors in the omega-3 group than in mice on the predominantly omega-6 fatty acid diet, demonstrating that higher levels of DHA and EPA may lead to development of more anti-inflammatory prostaglandins.

"This is one of the first studies showing changes in diet can impact the inflammatory response that may play a role in prostate cancer tumor growth," Aronson said. "We may be able to use EPA and DHA supplements while also reducing omega-6 fatty acids in the diet as a cancer prevention tool or possibly to reduce progression in men with prostate cancer."

The fish in the oceans are getting exhausted and fish costs more than cheaper land-based meat sources. We need genetically engineered crops that make more omega 3 fatty acids.

Monsanto might have genetically engineered high omega 3 fatty acid soybeans on the market in 5 or so years.

Monsanto has grown high-yielding, Omega-3-enriched soybeans, extracted the oil and shown that it has a pleasant taste and no fish odor that might turn off food companies and consumers, said Robb Fraley, chief technology officer. If the oil proves to be stable enough for use in processed foods, which must sit on store shelves without spoiling, and gains regulatory approval, he sees it appearing some time after 2010 in salad dressings, soy milks, margarines, yogurts and other foods.

"We have a lot of excitement about this," he said. "We now can open the door to a whole new way of delivering Omega-3s in the diet through food" rather than supplements in pill form.

Look for the Monsanto high omega 3 soy in 2011 or 2012.

Vistive Omega-3 is another modification in the pipeline, due to become available around 2011-2012. According to the company, the “enhanced oils represent an environmentally sustainable, economical source of Omega-3s, providing consumers with new options for omega-rich foods.”

Dupont is also hot on the trail of high omega 3 soy beans.

DuPont, one of the major movers and shakers in this area, revealed last week that it has developed a transgenic soybean with a long-chain omega-3 content of 40 per cent, and is heading for field testing of the crop.

DuPont's focus has been on maximising both EPA and DHA, and scientists based at the DuPont Experimental Station in Delaware, have expanded the standard procedure of desaturating and elongating the shorter chain fatty acids by using co-expression of an additional enzyme, omega-3 microsomal desaturase from the fungus Saprolegnia diclina, to convert the omega-6 very long chain polyunsaturated fatty acids (VLC-PUFAs) to omega-3s.

The previous article says BASF is also putting a big effort into development of high omega 3 crops.

High omega 3 soy will bring all sorts of benefits. See my posts Fish Consumption By Mom Makes Babies Smarter? and Fish In Diet Slows Rate Of Cognitive Decline for examples.

Share |      Randall Parker, 2006 August 01 06:23 PM  Aging Diet Cancer Studies

Bob Badour said at August 2, 2006 6:41 AM:

All of this assumes, of course, that it is mostly the fats and not other compounds in fish that make the difference. What if whatever causes the fishy smell is what has the most impact?

Jake said at August 2, 2006 8:01 AM:

I assume the genetically soybeans would be processed to extract the omega 3 for pills. I don't think Americans would eat enough soy based products to get any benefits.

Nick said at August 2, 2006 9:34 AM:

Doesn't flax seed oil provide the same benefits? I understand it has Omega-3's which are precursors to DHA and EPA, and which the body converts easily.

It helps with inflammatory skin conditions very effectively. Better than taking fish oil, in part because it's easier to take in larger quantities.

Brett Bellmore said at August 2, 2006 2:55 PM:

I'd like to suggest my favorite salad green: Purslane. There's scarcely a better plant based source of Omega 3 fatty acids, and it's remarkably tasty. From an article in the Journal of the American College of Nutrition,

"One hundred grams of fresh purslane leaves (one serving) contain about 300-400 mg of 18:3w3; 12.2 mg of alpha-tocopherol; 26.6 mg of ascorbic acid; 1.9 mg of beta-carotene; and 14.8 mg of glutathione.

Admittedly you'd have to eat it like a horse to get as much omega 3 as you'd really want, but every little bit helps.

Randall Parker said at August 2, 2006 3:11 PM:


Soy oil is used for cooking and in prepared foods. So you'd end up getting it in cakes or on french fries or with fried chicken.


The conversion efficiency is very low from ALA to EPA and DHA:

15g of flaxseed oil provides ca. 8g of ALA, which is converted in the body to EPA and then DHA at an efficiency of (5%-10%), and (2%-5%) respectively.[11]


I think that 18:3w3 is alpha-linolenic acid (ALA). See the link I used for the conversion efficiency and note what they say about the 18:3 being ALA. 20:5 (EPA) and 22:6 (DHA) are much better.

Ian said at December 15, 2006 11:59 AM:

You may not think you eat much soy, but I bet you do.. it's in a LOT of processed foods. Salad dressings, baked goods etc.

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