A team of researchers at McMaster University has developed a reliable and accurate blood test to track individual fat intake, a tool that could guide public health policy on healthy eating.
Establishing reliable guidelines has been a significant challenge for nutritional epidemiologists until now, because they have to rely on study participants faithfully recording their own consumption, creating results that are prone to human error and selective reporting, particularly when in the case of high-fat diets.
For the study, published in the Journal of Lipid Research, chemists developed a test, which detects specific non-esterified fatty acids (NEFAs), a type of circulating free fatty acid that can be measured using a small volume of blood sample.
“Epidemiologists need better ways to reliably assess dietary intake when developing nutritional recommendations,” says Philip Britz-McKibbin, professor in the Department of Chemistry & Chemical Biology at McMaster and lead author of the study
“The food we consume is highly complex and difficult to measure when relying on self-reporting or memory recall, particularly in the case of dietary fats. There are thousands of chemicals that we are exposed to in foods, both processed and natural,” he says.
The study was a combination of two research projects Britz-McKibbin conducted with Sonia Anand in the Department of Medicine and Stuart Phillips in the Department of Kinesiology.
In the 1980s and 1990s, Americans were told that eating less fat would reduce risk for cardiovascular disease and obesity. Why didn’t it work? Essentially, reducing total fat led to intake of more refined carbohydrates and less healthy fats, and both of these changes had negative health impacts.
Evolving Guidelines: Dietary advice on fat intake has evolved over the years. Based on strong evidence that diets high in saturated fats and cholesterol were associated with high blood cholesterol levels and a greater risk of heart attack, the 1980 U.S. Dietary Guidelines recommended Americans “avoid too much fat, saturated fat, and cholesterol.” The 1990 Dietary Guidelines added risk for obesity to the list of reasons to cut back on fats. (Since a gram of fat has more than twice the calories of a gram of protein or carbohydrate, reducing fat intake is the fastest way to reduce calorie intake.) But, soon thereafter, data began to emerge that low-fat diets were not having the expected results. “The 2000 Dietary Guidelines Advisory Committee noted the adverse effects of low-fat diets, and for the first time since their inception changed the guidance from low fat to moderate fat,” says Alice H. Lichtenstein, DSc, a member of that committee who is now a senior scientist at Tufts’ HNRCA and executive editor of Tufts Health & Nutrition Letter. From 2000 on, the Dietary Guidelines for Americans (DGA) recommended consuming a diet moderate in total fat that keeps saturated fat intake to under 10 percent of calories. The 2015 DGA emphasizes consuming foods rich in polyunsaturated fat. Some scientists feel that even this moderate fat restriction goes too far. Dariush Mozaffarian, MD, DrPH, dean of Tufts’ Friedman School of Nutrition Science and Policy and editor-in-chief of Tufts Health & Nutrition Letter sites evidence that a higher proportion of calories from fat is not harmful for either cardiovascular disease (CVD) or obesity, and in fact can lower risk if healthy (poly- and mono-unsaturated) fats replace refined starches and sugars. Continue reading →
According to the researchers, bad cholesterol can refer to both oxidized low-density lipoprotein (LDL) and small, dense LDL particles.
In a randomized, controlled feeding study, the researchers found that eating one avocado a day was associated with lower levels of LDL (specifically small, dense LDL particles) and oxidized LDL in adults with overweight or obesity. Continue reading →
I have posted on the nutritional value of the avocado a number of times. I wanted to run this as a refresher and also I thought it was beautiful. Sometimes folks are doubtful about avocados because they have fat, but it happens to be a very valuable fat that our bodies like.
A new Norwegian diet intervention study (FATFUNC), performed by researchers at the KG Jebsen center for diabetes research at the University of Bergen, raises questions regarding the validity of a diet hypothesis that has dominated for more than half a century: that dietary fat and particularly saturated fat is unhealthy for most people.
The researchers found strikingly similar health effects of diets based on either lowly processed carbohydrates or fats. In the randomized controlled trial, 38 men with abdominal obesity followed a dietary pattern high in either carbohydrates or fat, of which about half was saturated. Fat mass in the abdominal region, liver and heart was measured with accurate analyses, along with a number of key risk factors for cardiovascular disease.
“The very high intake of total and saturated fat did not increase the calculated risk of cardiovascular diseases,” says professor and cardiologist Ottar Nygård who contributed to the study. Continue reading →
Because low fat diets were the rage for a while, people have become confused about the value and necessity of including fats in their diets. I love coconut oil, a saturated fat. I eat it every day and have a Page of information – Coconut Oil – Why you should include it in your diet on it.
Until recently, when you visited the dairy aisle, chances are you headed straight for the blue carton of milk—the skim milk that is. But recent buzz about dairy fat may cause shoppers to pause in front of the oft-shunned red carton of whole milk or other full-fat dairy products, as research suggests that their relationship to heart health is more complex than was once believed. While most studies to date have focused on the association between dairy fat and cardiovascular risk factors, few have examined the relationship to actual onset of cardiovascular disease.