Dr. Stephanie Venn-Watson, Author of The Longevity Nutrient, Talks About Saturated Fats on Good Day New York

As the Debate Around Dietary Saturated Fats Heats Up in Anticipation of the Release of USDA's Updated Dietary Guidelines for Americans, the Science Behind a Healthy Saturated Fat Continues To Grow

NEW YORK, Jan. 6, 2026 /PRNewswire/ -- With the upcoming and highly anticipated release of USDA's 2026-2030 Dietary Guidelines for Americans, the debate around whether saturated fats are bad, neutral, or good is heating up, including recently published peer-reviewed studies focusing on dietary saturated fats and our health.

Dr. Venn-Watson, the world's leading expert on C15:0 and author of the USA Today Bestseller Simon & Schuster book, The Longevity Nutrient, was recently on Good Day New York to discuss the latest studies on saturated fats and why it has been so hard to define their role.

"A big reason why the science has been so confusing is because not all saturated fatty acids are created equal," said Venn-Watson. "When studies lump all saturated fats from all food types for all people into a single category, it's nearly impossible to get to the truth. The science is becoming indisputable that, while some types of even-chain saturated fats are proinflammatory and may be harmful, some odd-chain saturated fats — especially C15:0 — can be beneficial and even essential to our health."

C15:0 (also called pentadecanoic acid) is a dietary odd-chain saturated fatty acid primarily present in milkfat, as well as some types of fish. C15:0 was initially discovered as beneficial when Dr. Stephanie Venn-Watson, a veterinary epidemiologist, was caring for older Navy dolphins and found that higher dietary and circulating C15:0 levels predicted the healthiest aging dolphins. During the past decade since that discovery, C15:0 has emerged as the first essential fatty acid to be discovered in nearly a century, since omega-3s; the role of C15:0 as an essential fatty acid has been further backed by multiple independent teams — including use of hallmark models of nutritional deficiencies. Today, there are over 100 peer-reviewed studies supporting C15:0's role as a core nutrient needed to support healthy growth and development in youth, as well as healthy aging in adults.

A recently published metaanalysis in Advances in Nutrition evaluated dose-response relationships between 27 different fatty acids and the risk of developing type 2 diabetes. This study, which included 27 prospective cohort studies following over 100,000 adults across the U.S., Europe, Asia, and Australia for periods of time ranging from 2.5 to 42 years, showed that higher levels of two odd-chain saturated fats, C15:0 and C17:0, were associated with the lowest risk of developing type 2 diabetes. Specifically, every 0.1% increase in C15:0 levels was associated with a 32% lower risk of developing type 2 diabetes. In comparison, higher omega-3 levels were associated with 3% to 8% lower risks of developing type 2 diabetes. Higher levels of C16:0, an even-chain and proinflammatory saturated fatty acid, were associated with a higher risk of developing type 2 diabetes.

Findings from this latest study, specifically that C15:0 was associated with better health and C16:0 was associated with poorer health, are consistent with numerous prior prospective cohort meta-analyses evaluating long-term outcomes related to type 2 diabetes and cardiovascular disease.

Beyond association, experimental studies have shown that C15:0 has direct dose-dependent mechanisms of action and efficacy in preclinical models relevant to protecting long-term cardiometabolic, gut, red blood cell, immune, and liver health. Further seven randomized clinical trials support that raised intake of C15:0 increases C15:0 levels, and these raised levels were associated with supported vascular, cholesterol, gut, red blood cell and liver health. Similar studies have shown the opposite for C16:0.

While our primary dietary source of C15:0 is dairy fat, this fat source also has much higher amounts of C16:0. A recently published cross-over clinical trial with healthy adults showed that increasing one's daily amount of dairy fat resulted in increased C15:0 levels, which was linearly associated with improved vascular function. In contrast, this same study showed that dairy fat intake also increased C16:0 levels, which were associated with increased blood pressure.

"Clear and opposing health effects of different saturated fats mean that nutritional recommendations should be refined to avoid the risk of causing more harm than good," said Venn-Watson. "The impetus behind Congress' Dietary Recommendations for Americans, released in 1977, was to address the rise in cardiovascular disease, type 2 diabetes, and obesity by limiting saturated fat intake. Instead of getting healthier, however, we as a nation have gotten sicker. Mounting studies support that we need adequate C15:0 to support our long-term health, including the potential to lower our risk of developing cardiovascular disease and type 2 diabetes."

While the prevalence of type 2 diabetes and obesity in 1980 were around 3% and 15%, respectively, today they are approximately 10% and 40%. Further, cardiovascular diseases are expected to increase over the next 30 years.

"With increased conversations around the upcoming release of the USDA's 2026-2030 Dietary Guidelines, we need to include discussions about the robust body of science around healthy versus unhealthy saturated fatty acids," said Venn-Watson, "By doing so, we can understand not only why studies on saturated fats have been so messy, but how we can meaningfully improve health by acknowledging that some types of saturated fats, specifically C15:0, may be crucial to protecting public health. The breadth and depth of science supporting C15:0 as a healthy nutrient simply cannot and should not be ignored."

About The Longevity Nutrient: The Longevity Nutrient (Simon & Schuster) follows Dr. Stephanie Venn-Watson's discovery of C15:0 as an emerging essential nutrient while caring for older Navy dolphins and walks readers through a decade and over a hundred peer-reviewed studies supporting C15:0's role as a core nutrient needed to restore global health.

About Seraphina Therapeutics, Inc.: Seraphina Therapeutics, Inc. is a health and wellness company dedicated to advancing global health through essential nutrients and longevity-supporting geroprotectors, including fatty15, an award-winning C15:0 supplement. Through rigorous science, the company develops fatty acid supplements to strengthen cells, keep mitochondria working, and advance cellular homeostasis to counter age-related breakdown. With its team of industry-leading scientists, Seraphina Therapeutics challenges long-held approaches to nutrition, enabling the creation of novel health products designed to support quality of life. For more information, please visit DiscoverC15.com and fatty15.com.

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