Are nutritional C15:0 deficiencies driving the rise in cancer among younger people?

Healthy Aging

Why is cancer increasing among young people?

We are back from the 9th Annual Biohacking Conference, which was a tour de force of all things being tested to help us live longer. Cryochambers, hyperbaric oxygen, ice baths, salt caves, and more.

As we settle back home, we continue to follow the science – specifically, the science on C15:0 – to help us live as healthily as possible, for as long as possible. Here at Science Says!, we have some catching up to do on the latest peer-reviewed science that has been published on C15:0 during 2023.

This week, let’s talk about a study published in Nutrients, which evaluated fatty acid profiles and their relation to risk of developing cancer – specifically, colorectal cancer.

Colorectal cancer is on the rise in younger people.

In their recent review, Spaander et al. discuss the increasing incidence of colorectal cancer among people under 50 years old, referred to as young-onset colorectal cancer. It is estimated that approximately 1 out of 10 colon cancers and 1 out of 4 rectal cancers will be among young people by 2030. Imperiale et al. looked at risk factors for colorectal cancer among young male Veterans. They found the usual suspects, including higher body mass index (BMI), presence of multiple chronic conditions, and a relative with a history of similar cancers. While helpful, it remains unclear why more younger people are developing colorectal cancer.

So, what did the Nutrients study evaluate?

To better understand the role of fatty acids on colorectal cancer risk, many prior studies have looked at either 1) dietary intake or 2) blood levels of fatty acids. Those dietary studies, however, depend on how well people report what they actually eat (just think if you had to list everything you ate last week…). And while measuring fatty acid blood levels is much more reliable, it can be difficult to determine what these blood levels mean without having dietary intake information.

As such, a giant “study of studies” was conducted by Lu et al., which included 54 original studies and 2 million people, including 52,000 people with colorectal cancer. They combined both fatty acid dietary and blood data to determine which fatty acids were associated with either a lower or higher risk of colorectal cancer.

Among fatty acid blood levels, C15:0 was the only predictor of lower cancer risk.

Yes, we know Science Says! is focused on C15:0 science. But really. Among blood levels determined for 18 different fatty acids – including other saturated fatty acids, monounsaturated fatty acids, and omega-3 and omega-6 fatty acids – only higher C15:0 (pentadecanoic acid) was associated with a lower risk of having colorectal cancer.

Reported dietary fatty acid intake was less clear. While higher total saturated fatty acid dietary intake was protective against colorectal cancer risk, no single dietary saturated fat (including C15:0) made the statistically significant cut.

Given the difficulty of accurately reported dietary information, and the much-higher reliability of measuring fatty acid blood levels, this giant study-of-studies concluded that C15:0’s link to a lower cancer risk was meaningful.

Ah, but association doesn’t mean causation, right?

Right! While this study’s results are encouraging, the conclusions are simply about association. Just because higher C15:0 blood levels are associated with lower colorectal cancer risk, doesn’t mean that C15:0 causes that lowered risk. That is why epidemiological studies – including mega-large studies of studies – are great for generating hypotheses to be tested in the lab and in clinical trials.