New research finds that different fats affect people with diabetes differently. The studies looked at saturated versus unsaturated fats, omega-3 versus omega-6 oils, and trans fats. What kind of fats are best for people with diabetes to eat?
Kinds of fats
First, what do the terms “saturated fat,” “unsaturated fat,” and “trans fat” mean? How do they affect our bodies?
Fats are made of chains of carbon atoms attached to each other. Those links leave open spaces where other atoms, such as hydrogen and oxygen, can attach.
In saturated fat, there are “no double bonds between carbon molecules because they are saturated with hydrogen molecules.” With all spaces taken, the fat becomes solid and stable. It doesn’t break down easily, and it can form globs and plaques that attach to your arteries. Saturated fats include most animal fat and some vegetable fats like palm oil.
Unsaturated fat is not fully saturated with hydrogen atoms. Monounsaturated fat has one unsaturated carbon bond; polyunsaturated fat has more than one. Unsaturated fats break down more easily and are usually liquid at room temperature.
The terms omega-3, omega-6, and omega-9 refer to where the unattached spaces are in the carbon chain. They have slightly different affects in the body.
Trans fats start out as unsaturated fats and have hydrogen added in an industrial process. They are called “hydrogenated vegetable oils” on food labels. They become artificially saturated and break down somewhat differently than natural saturated fat.
Research on fats
Scientists are continually learning more about fats. Here is some fat research news.
• Avoid palm oil — a German study of 14 lean, healthy males found that one dose of palm oil can increase insulin resistance (IR) by more than 25 percent, an effect that lasted up to 8 hours. Subjects also had an increase in fat deposits in the liver and changes in their metabolism “similar to those experienced by people with diabetes.”
Researchers got similar results in a study of healthy, nonobese mice. This is significant because palm oil is being used more widely as a replacement for butter or other fats. But this study and some others show that it is not healthier. It also has major environmental effects, because rainforests are clear cut to make room for palm tree plantations.
• University of California, Davis, researchers cautioned that all saturated fats can cause diabetes. “Fat build-up inside (muscle) cells,” they wrote, “creates toxic fatty breakdown products and free radicals that ‘block’ the insulin-signaling process, close the ‘glucose gate,’ and make blood sugar levels rise.”
Similarly, an Israeli study found that eating red meat and grilled meat is associated with insulin resistance and fatty liver. Over 800 people filled out questionnaires on consumption of meat and how they cooked it. High consumption of red meat was associated with a 50 percent increased risk of insulin resistance, and eating grilled meat or meat baked or roasted at high temperature was linked with a roughly double risk of insulin resistance.
Not all studies agree about meat. A Spanish study found no significant link between diabetes risk and red or processed meat consumption. Researchers said these results might reflect that Spaniards don’t eat that much meat anyway and cautioned the results might not apply to people eating a standard American diet.
• Omega-6 fatty acids may improve heart health, according to a Finnish study. Researchers found that having high levels of the omega-6 fat called linoleic acid in the blood were linked to a lower chance of all-cause death and of cardiovascular death. Omega-6 fatty acids are present in plant-based foods such as vegetable oils, seeds, nuts, whole grains, and beans.
This is interesting because other studies have found that too much omega-6 is not good for us, and most people need more omega-3s. (I’m not sure what to think about that. I think they are both unsaturated, and probably both good if you don’t overdo them.)
Trans fats are widely used because they break down more slowly than natural fats, increasing the shelf life of packaged foods that use them. Americans had been consuming large amounts of margarine and other cooking products that contain trans fat, especially in packaged, baked, and fried food.
Trans fats are known to raise levels of LDL (“bad”) cholesterol and lower levels of HDL (“good”) cholesterol. In many studies, trans fat consumption increased people’s risk of heart attacks, strokes, and Type 2 diabetes.
A decrease in trans fat worldwide is good news. The elimination of industrial trans fats “can prevent millions of premature deaths and chronic diseases worldwide,” said Dr. Walter Willett, professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health, in an interview with CNN.