NMMF Dolphin Study Discovers How Saturated Fat May Prevent Diabetes.
- Dolphins can develop metabolic syndrome, also called prediabetes in humans.
- A modified diet higher in heptadecanoic acid, a saturated fat present in some fish and butter, reversed metabolic syndrome in dolphins.
- In addition to some fish, C17:0 is present in whole fat dairy products and rye.
NMMF leads ongoing research to understand and improve dolphin health. As part of this work, NMMF scientists previously discovered that bottlenose dolphins – including those in the wild – can develop metabolic syndrome, a subclinical condition called prediabetes in humans. A new study led by the NMMF and published in PLOS ONE today discovered a saturated fat, called heptadecanoic acid (or C17:0), that may help reverse metabolic syndrome in dolphins and humans.
The study, led by Dr. Stephanie Venn-Watson, Director of NMMF’s Translational Medicine and Research Program, explored the dolphin diet for fish nutrients that may be protective against metabolic syndrome. Specifically, they focused on fatty acid blood levels in 49 dolphins, as well as fatty acids in their dietary fish.
Surprisingly, the big winner among the 55 fatty acids was a saturated fat, C17:0. Dolphins with higher levels of C17:0 in their blood had lower insulin and triglycerides. The study also showed that while some fish have high levels of heptadecanoic acid, other fish types had none. Further, when six dolphins with low C17:0 were then fed fish high in C17:0, elevated insulin, glucose, and triglycerides normalized within six months. Key to this surprising outcome was reversal of high ferritin, an underlying cause of metabolic syndrome. Blood ferritin levels decreased in all six dolphins within three weeks on the new diet.
C17:0 is a saturated fat found in dairy fat, rye, and some fish. The published PLOS ONE study showed no detectable heptadecanoic acid in nonfat dairy products, some amount in lowfat dairy products, and the highest levels were found in whole fat milk, yogurt, and especially butter. The fish with the highest heptadecanoic acid content was mullet.
Given these findings, Dr. Venn-Watson proposes that widespread movement away from whole fat dairy products in human populations may have created widespread C17:0 deficiencies. In turn, this dietary deficiency may be playing a role in the global diabetes pandemic. NMMF’s discovery aligns well with growing scientific evidence demonstrating that cholesterol and some fats may not be as bad as we once thought. Earlier this year, the American Dietary Guidelines changed its recommendations related to fat, including removing the need for most people to limit their dietary cholesterol intake (high cholesterol comes primarily from what our body produces, not what we eat). Today, the Centers for Disease Control and Prevention estimates that over 86 million people in the U.S. have metabolic syndrome, equal to one in every three adults.
NMMF is partnering with children’s hospitals to see if children with metabolic syndrome and diabetes also have low heptadecanoic acid levels. They also hope to study how changes in ocean prey may be negatively impacting the metabolism of wild dolphins.