EarthSpin

FIG. 1. Paste made from avocado flesh in a lab-scale malaxer where the oil droplets start to coalescence before oil extraction. Credit: John Almazan

Avocadoes are having a moment. The nutritional benefits promote heart health and reduce inflammation, blood pressure, and cholesterol. Not to mention the popularity of avocado toast.

Despite the rise in consumer interest, there are no standards to define the chemical and physical characteristics of avocado oil. Without an internationally defined standard, consumers are left vulnerable to adulterated or fraudulent avocado oil in the marketplace.

“Currently selling and buying avocado oil is like playing a boardgame with no rules,” said Selina Wang, department vice-chair and associate professor of Cooperative Extension in the Department of Food Science and Technology at the University of California, Davis. “With no enforceable standards in place, cheaters win and honest players get taken advantage of.”

Read Full Post »

Humans have evolved to eat a variety of foods. No one component is entirely bad or entirely good. Many diets popular today, approach nutrition through a narrow, simplified lens. Every decade one component of our diet is placed center stage as the villain that is responsible for all of our woes. In recent decades, the spotlight has been turned on fats.

Fat is essential, providing a source of energy and a feeling of satiety. There are essential fatty acids that humans cannot produce, including linoleic acid (omega- 6) and alpha-linolenic acid (omega-3). Both fatty acids are obtained from the food we eat and play a critical role in major cellular events, including metabolism, inflammation, cell differentiation, and cell death. Some dietitians and nutritionists have advocated for eating an equal amount of omega-6 and omega-3 fatty acids, resulting in a 1:1 ratio. This diet is presumed to mimic the ancient human diet, though no definitive data supports what early humans actually ate consistently. The modern American diet ranges from a value of 10:1 to 15:1.

The overarching nutritional message has been that the modern diet suffers from an “omega imbalance.” The imbalance is a ‘concern,’ because omega-6 fatty acids, which skews the index to higher numbers, have been assumed to promote poor health outcomes and disease, including increased ‘bad’ cholesterol (LDL), inflammation, and coronary heart disease. Surprisingly, no randomized controlled clinical trials actually support any of these claims.

The concept of the omega-6:omega-3 ratio is “flawed and unhelpful,” says William Harris, professor of basic biomedical sciences at the University of South Dakota, in Vermillion, South Dakota, USA.

Harris is the founder and president of the Fatty Acid Research Institute, a non-profit research and education organization created to further the study of fatty acids and disease. To expand on Harris’s point, measuring the ratio is difficult because each fatty acid appears as various species in different ratios in different reservoirs in the body. According to Harris, this simple metric has “both theoretical and practical complications” that create fundamental misunderstandings that have cascaded through the field. He has published numerous articles describing the lack of scientific validation to support using this ratio as an indicator of healthful diet.

Martha Belury, Carol S. Kennedy professor of human nutrition in the Department of Human Sciences at the Ohio State University, Columbus, Ohio, USA, concurs with Harris’s assessment. She believes it is time to move away from the omega-6:omega-3 ratio and re-evaluate the benefits of the much maligned omega-6 fat.

“Science and health are short-changed if we oversimplify,” said Belury. “While omega-3 has an important role in health, omega-6 has a pivotal role to play as well. This is an important message for consumers and practitioners.”

Read Full Post »