Tag Archives: omega-6

Fuss about food – Omega 3

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fishoil.jpgAfter the big ‘fat is bad’ push of the 1980s and 1990s, we are finally coming around to the idea that some fats are good for us.

But which ones?

The good ones are Polyunsaturated fats (PUFAs) and Monounsaturated fats (MUFAs).

Omega 3 and 6 fats are PUFAs and are classed as essential.
Our bodies cannot manufacture these so we need to make sure we are eating foods which contain them.

It seems like every day we hear about something else that we should be eating or drinking. So what makes Omega 3 special?

We need good fats for a whole host of things – every cell in your body relies on fat to survive. They are essential for nerve, heart and brain health and for nearly all of the body’s basic functions.

We seem to have no problem getting enough Omega 6 fat but there is one big catch – Omega 6 fats are dependent on Omega 3 to produce optimal health benefits and are only considered good fats when consumed in moderation.

Omega 3 fats have an amazing role in your body as an anti-imflammatory. Consuming them reduces your risks of developing heart disease, arthritis and cancer. It is widely acknowledged to have a pivotal role in the prevention of heart disease.

Omega 6 fats, while helpful in reducing bad cholesterol, can promote inflammation within our bodies when too much is consumed – a very undesirable quality. The developed world, as a whole, is extremely inflamed.

In the US, diets tend to contain up to 25 times more Omega 6 than Omega 3 fats.

Mediterranean diets have long been studied to identify exactly what promotes heart health and longevity. These studies have indicated that it is the healthy balance between Omega 3 and 6 fatswhich leads to a longer and healthier life.

People who follow such a diet are much less likely to develop heart disease. The mediterranean diet traditionally contains much reduced levels of meat consumption, which is a major source of omega 6 fats. It focuses on foods rich in omega 3 fats, including wholegrains, fresh fruit and vegetables, garlic, fish and olive oil. Moderate intake of wine also adds something to the balance.

If you only take one supplement a day, health professionals are almost all in agreement that it should be a fish oil supplement.

Clinical evidence suggests that EPA and DHA (eicosapentaenoic acid and docosahexaenoic acid, the two omega-3 fatty acids found in fish oil) help reduce risk factors for heart disease, including high cholesterol and high blood pressure. Fish oil has been shown to lower levels of triglycerides (fats in the blood), and to lower risk of death, heart attack, stroke, and abnormal heart rhythms in people who have already had a heart attack.

If you are sceptical about the importance of these fats, consider the symptoms of someone suffering from a defiency in Omega 3; tiredness, poor memory, dry skin, heart problems, mood swings, depression and poor circulation.

Omega 3 fats are highly concentrated in the brain and appear to be important for cognitive (brain memory and performance) and behavioral function. So if you feel like you need a memory or energy boost, you could find your answer in changing your diet just a little bit.

If you are on blood thinners or diabetes medication, you should consult your GP before starting to take fish oil supplements.

Later this week we will be examining a sinner of the fat world – Trans fats.

Low fat diet helps prevent prostate cancer in mice

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Los Angeles: Us scientists have found that have demonstrated that lowering intake of the type of fat common in a Western diet helps prevent prostate cancer in mice.

UCLA’s Jonsson Cancer Center and the Department of Urology carried out the study, which is published in the April editon of the journal Cancer Research.

Scientists excamined the effects of fat from corn oil, which is made up primarily of omega-6 fatty acids, or the polyunsaturated fat commonly found in the Western diet. Omega-6 fats are found in high levels in baked and fried goods, said William Aronson, a Jonsson Cancer Center researcher and the study’s senior author.

Researchers fed one group of mice a diet with about 40 percent of calories coming from fat, a percentage typical in men eating a Western diet. The other group received 12 percent of their calories from fat, a figure considered to be a very low fat diet.

The low-fat group had a 27 percent reduced incidence of prostate cancer. They also studied cells in the prostate that were precancerous, or would soon become cancer, and found that the cells in the mice eating the low-fat diet were growing much more slowly than those in the high-fat group.

Previous studies in Mr Aronson’s lab showed that a low-fat diet slowed the growth of aggressive human prostate cancers in mice and helped the mice live longer. However, whether such a diet could prevent prostate cancer was unknown.

“We didn’t know what to expect in terms of the role of reducing dietary fat in preventing prostate cancer,” said Aronson, a professor of urology. “We think this is an important finding and we are presently performing further studies in animal models and conducting clinical trials in men.”

Using a novel mouse model that develops cancer within the prostate over a period of six to nine months, Mr Aronson and his team were able to study cancer incidence and cell growth. The mice were assigned to a dietary fat group at three weeks of age, when they first started ingesting food. The prostates and prostate cells were studied at seven months.

During the growth phase when the precancerous lesions develop, called PIN or prostate intraepithelial neoplasia, Aronson found that mice on the low-fat diet had higher levels of a protein in their bloodstreams that binds to insulin like growth factor, which spurs prostate cancer growth. Aronson believes that lowering dietary fat and increasing levels of the binding protein slows prostate cancer development by cutting off the growth factor that allows prostate cancer to thrive.

“A low-fat, high-fiber diet combined with weight loss and exercise is well known to be healthy in terms of heart disease and is known to reduce the risk of heart attacks and strokes, so that would be a healthy choice to make,” Aronson said. “Whether or not it will prevent prostate cancer in humans remains to be seen.”

Mr Aronson is now conducting a short term study in men who are randomly assigned to a Western diet higher in polyunsaturated fat or a low-fat diet with fish oil supplements. The next step is to see how these diets affect malignant and benign human prostate tissue, Aronson said.

“We’re looking at specific markers and growth factors in human tissue known to be important for development and progression of prostate cancer,” he said. “It’s this work we hope will lead to longer term prevention strategies incorporating dietary changes.”

Omega 3 may slow prostate cancer

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Los Angeles: Increasing the amount of omega-3 fatty acids and reducing omega 6 fatty acides could slow the progression of prostate cancer, according to a new study by the UCLA School of Medicine.

In the study, published in Clinical Cancer Research, mice were implanted with human prostate cancer cells and then divided into two group. One group, fed on a typical Western diet with an omega 6 to omega 3 ratio of 15 to 1, while the intervention group was fed the fatty acids in ratio of 1 to 1.

The cancer cells in the intervention group grew 22 per cent slow than the others. In addition the rate of growth in tumours, the final size and PSA levels were all lower

Senior author, Dr Willian J Aronson said that the study showed that altering the fatty acid ratio found in the typical Western diet to include more omega-3 fatty acids and decreasing the amount of omega-6 fatty acids reduced prostate cancer tumor growth rates and PSA levels in mice. He said more research was needed before any clinical recommendations could be made for human.

Omega 6 promotes cancer cell growth in prostate

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San Francisco: Omega-6 fatty acids, found in foods such as corn oil, resulted in the faster growth of human prostate tumors in cell culture , according to a study conducted at the San Francisco VA Medical Center.

The study which is published in January’s Cancer Research discovered that an omega-6 fatty acid known as arachidonic acid turns on a gene signaling pathway that leads directly to tumor growth.

Lead researcher Millie Hughes-Fulford, PhD, director of the Laboratory of Cell Growth at SFVAMC and professor of medicine at the University of California said it had been observed that the additin of omega 6 to the growth medium, the tumours grew twice as fast as those without it.

She said: “Investigating the reasons for this rapid growth, we discovered that the omega-6 was turning on a dozen inflammatory genes that are known to be important in cancer. We then asked what was turning on those genes, and found that omega-6 fatty acids actually turn on a signal pathway called PI3-kinase that is known to be a key player in cancer.”

Hughes-Fulford says the results are significant because of the high level of omega-6 fatty acids in the modern American diet, mostly in the form of vegetable seed oils such as corn oil – over 25 times the level of beneficial omega-3 fatty acids, which are found in canola oil, fish, and green vegetables. She notes that over the last 60 years, the rate of prostate cancer in the U.S. has increased steadily along with intake of omega-6, suggesting a possible link between diet and prostate cancer.

The study results build on earlier work in which Fulford and her research team found that arachidonic acid stimulated the production of an enzyme known as cPLA-2, which in turn caused a chain of biochemical reactions that led to tumor growth. In the current paper, the researchers have “followed that biochemical cascade upstream to its source,” Hughes-Fulford says. “These fatty acids are initiating the signal pathway that begins the whole cascade.”

Hughes-Fulford and her fellow researchers also found that if they added a non-steroidal antiflammatory or a PI3K inhibitor to the growth media, interrupting the signal pathway, the genes did not get turned on and increased tumor cell growth did not take place.

Currently, Hughes-Fulford is conducting a study in which research animals are fed diets with different levels of omega-3 and omega-6 fatty acids, “to see how the tumors grow in animals.”

Hughes-Fulford says that her study results have directly influenced her own diet. “I’m not a physician, and do not tell people how to eat, but I can tell you what I do in my own home,” she says. “I use only canola oil and olive oil. We do not eat deep-fried foods.”

Omega-6 fatty acids may cause dry eyes

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London: Women who consume a greater amount of omega-6 fatty acids have an increased incidence of dry eye syndrome while women consuming greater amounts of omega-3s have a reduced risk of this condition, a new study has found.

Researchers studied 32,470 female health professionals aged 45-84 years who participated in the Women’s Health Study. The study authors determined the women’s fatty acid intakes by using a validated food-frequency questionnaire. They assessed the incidence of dry eye syndrome in the patients by having the subjects report if they had developed a clinically diagnosed case. Of the study sample, 1,546 (4.7 percent) reported dry eye syndrome.

After adjustment for demographic factors, hormone therapy, and total fat intake, a higher ratio of omega-6 to omega-3 fatty acid consumption was associated with a significantly increased risk of dry eye syndrome. Subjects who ate the most omega-3s, however, had a lower risk of dry eye syndrome. The researchers found a 17 percent reduced risk of dry eye syndrome for women consuming the most omega-3s compared to women consuming the least.

According to the researchers, “These results suggest that a higher dietary intake of omega-3 fatty acids is associated with a decreased incidence of dry eye syndrome in women.”