This Nutrient May Improve Fasting Insulin For People With Diabetes
Omega-3 fatty acids have long been associated with heart and brain health, but their potential role in metabolic health is a little more complicated. While these essential fats are often touted for their ability to support healthy inflammation and blood sugar balance, clinical trials in people with diabetes haven't always shown clear benefits.
For people with diabetes, maintaining healthy blood sugar is only part of the picture. Insulin sensitivity, inflammation, and the health of the body's smallest nerve fibers can all play a role in long-term complications, making it worth understanding whether nutrition can support these systems, too.
So, what does the research actually say about omega-3 supplementation for people with diabetes? A new meta-analysis1 pooled data from clinical trials to take a closer look at the question. Here's what researchers found—and what the results mean for your omega-3 routine.
About the study
Researchers set out to evaluate how omega-3 supplementation affects blood sugar control, blood fats, inflammation, and nerve health in people with diabetes. They were particularly interested in its effects on blood lipids, blood sugar regulation, inflammation, oxidative stress, and small-fiber nerve health.
They pulled data from 11 trials that all had:
- Participants with type 1 diabetes, type 2 diabetes, or gestational diabetes, or were at high risk of developing diabetes
- Omega-3 supplement doses ranging from 500 milligrams to 8 grams a day, from both fish-based sources (EPA and DHA) and plant-based ones (perilla and flaxseed oils)
- A follow-up period ranging from six weeks to five years
- Direct measures of metabolic health like HbA1c, fasting blood sugar, fasting insulin, HOMA-IR (a calculation that estimates how well cells respond to insulin), LDL and HDL cholesterol, triglycerides, markers of inflammation and cell damage, and the density of tiny nerve branches in the front of the eye
Omega-3s may benefit fasting insulin
Two results moved in omega-3's favor, and both have to do with insulin.
- Fasting insulin dropped: Across two trials, people taking omega-3s ended up with lower fasting insulin than those on a placebo.
- Insulin resistance improved: Across three trials, HOMA-IR scores came down with omega-3s. A lower score points to cells responding better to insulin, so the body doesn't have to pump out as much of it.
- Blood sugar stayed put: HbA1c and fasting blood sugar looked the same in the omega-3 and placebo groups.
- Most cholesterol markers held steady: LDL, HDL, and triglycerides were unchanged overall, though triglycerides did come down in the trials that ran 13 to 26 weeks.
- Inflammation markers didn't budge: That includes C-reactive protein, along with several measures of cell damage.
The authors are direct about what this means. Omega-3s aren't a direct blood-sugar-lowering tool. What the insulin numbers point to is a slight nudge in how efficiently the body uses the insulin it already makes. Those insulin findings came from a small handful of trials with small groups of people, and the researchers rated their confidence in them as low.
They may also support nerve health
The other finding involved the tiny nerve branches in the cornea, the clear front surface of the eye. Two trials measured them, and both showed improvement with omega-3 supplementation.
Why the eye? Diabetes can damage small nerve fibers (and blood vessels) over time, which often shows up as tingling, numbness, or pain in the feet and hands. The nerve fibers in the cornea can be measured without a needle or biopsy, so researchers use them as an early read on nerve damage happening elsewhere in the body.
Both trials pointed towards omega-3 supplements supporting this indicator of eye health. But neither study tracked whether people noticed or felt a difference. Future studies will hopefully look into this more.
How to get more omega-3s
The review notes that international guidelines generally point to about 250 to 500 milligrams a day of EPA and DHA for the general population to support heart health. A few ways to get there:
- Fatty fish: Salmon, tuna, and mackerel are the main food sources of EPA and DHA.
- Fish oil supplements: These offer a therapeutic dose (ideally 1,000+ milligrams per serving), and a high-quality product can limit exposure to contaminants found in some fish. Here are our top (expert-vetted) picks for the best omega-3 supplements out there.
Higher doses are sometimes used under a doctor's supervision for specific issues, like very high triglycerides. Anyone managing diabetes should check with their provider first, since medications and other health conditions factor in.
The takeaway
Omega-3s may have a role in supporting metabolic health beyond the outcomes we typically associate with them. This analysis found promising signals for insulin sensitivity and small-fiber nerve health. But most of us aren't getting enough of these crucial fats in our diet. Focus on incorporating fatty fish into your weekly menu in addition to a starting a high-quality. omega-3 supplement for more targeted support.