Fish oil, a readily available supplement, boasts a wealth of omega-3 fatty acids, renowned for their diverse health benefits. These include enhanced cardiovascular and cognitive function, reduced depressive symptoms, and improved dermatological health. Emerging research suggests that omega-3s may also play a role in facilitating weight loss. However, the scientific community remains divided, with studies yielding conflicting results regarding this potential benefit. This article aims to provide a comprehensive overview of the current evidence surrounding omega-3s from fish oil and their impact on weight management.
Decoding Fish Oil Omega-3s
Omega-3 fatty acids are categorized into two primary groups:
- Essential Omega-3 Fatty Acids: Alpha-linolenic acid (ALA) stands as the sole essential omega-3 fatty acid. Being essential signifies that the human body cannot synthesize ALA, necessitating its acquisition through dietary sources. ALA is abundant in various plant-based foods, with walnuts, hemp seeds, chia seeds, flaxseeds, and their corresponding oils serving as the richest sources.
- Long-Chain Omega-3 Fatty Acids: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the most well-known long-chain omega-3 fatty acids. These are predominantly found in fish oil and fatty fish, as well as seafood, algae, and algae oil.
While the body can convert ALA into EPA and DHA, this conversion process is not very efficient in humans. It is estimated that only about 2-10% of the ALA consumed is converted into EPA and DHA. Consequently, many health professionals recommend a daily intake of around 200-300 mg of EPA and DHA. This can be achieved by consuming approximately two portions of fatty fish per week or through supplementation.
EPA and DHA play crucial roles in numerous essential body functions, particularly in brain and eye development and function. Studies indicate that maintaining adequate levels of EPA and DHA may also contribute to the prevention of inflammation, depression, breast cancer, and attention deficit hyperactivity disorder (ADHD).
Fish oil omega-3 supplements are widely available in various forms, including oil drops and capsules, for convenient daily intake.
Read also: CPAP Machine Benefits
The Potential of Fish Oil in Reducing Hunger and Appetite
One potential mechanism by which fish oil omega-3s may aid in weight loss is by reducing hunger and appetite. This effect can be especially beneficial for individuals adhering to weight loss diets, which often lead to increased feelings of hunger.
In one study, healthy individuals on a weight loss diet consumed either less than 0.3 grams or more than 1.3 grams of fish oil omega-3s per day. The group consuming the higher dose of fish oil reported feeling significantly fuller for up to two hours after a meal.
However, it's important to note that these effects are not universally observed. In another small study, healthy adults not following a weight loss diet were given either 5 grams of fish oil or a placebo each day. The fish oil group reported feeling around 20% less full after a standard breakfast and experienced a 28% stronger desire to eat.
Furthermore, several studies in patients with cancer or renal disease have reported increased appetite or calorie intake in those given fish oil, compared to others given a placebo.
Interestingly, one study observed that fish oil omega-3s increased the levels of a fullness hormone in obese people, but decreased levels of the same hormone in non-obese people.
Read also: Healthy food access with Highmark Wholecare explained.
These findings suggest that the effects of fish oil on hunger and appetite may vary depending on an individual's health status and diet. However, further research is needed before definitive conclusions can be drawn.
Fish Oil's Potential Role in Boosting Metabolism
Another way fish oil omega-3s may contribute to weight loss is by increasing metabolism. Metabolism can be assessed by measuring metabolic rate, which indicates the number of calories burned each day. A higher metabolic rate translates to more calories burned, making it easier to lose weight and maintain weight loss.
One small study reported that when healthy young adults took 6 grams of fish oil per day for 12 weeks, their metabolic rates increased by around 3.8%. In another study, healthy older women who took 3 grams of fish oil per day for 12 weeks experienced an increase in their metabolic rates by approximately 14%, which is equivalent to burning an extra 187 calories per day. More recently, a study found that when healthy adults took 3 grams of fish oil per day for 12 weeks, their metabolic rate increased by an average of 5.3%.
Most studies reporting increases in metabolic rates also observed an increase in muscle mass. Muscle burns more calories than fat, thus an increase in muscle mass may explain the higher metabolic rates observed in these studies.
That said, not all studies have observed this effect. Thus, more studies are needed to understand the exact effects of fish oil on metabolic rates.
Read also: Risks of Salad Dieting
Amplifying the Effects of Exercise with Fish Oil
The metabolic effects of fish oil may extend beyond simply increasing the number of calories burned each day. Research suggests that consuming fish oil may also amplify the number of calories and amount of fat burned during exercise.
Researchers believe this happens because fish oil may help you switch from using carbohydrates to fat as a source of fuel during exercise. One study reports that women given 3 grams of fish oil per day for 12 weeks burned 10% more calories and 19-27% more fat when they exercised. This finding may explain why some studies have found that taking fish oil supplements in combination with exercise was more effective at reducing body fat than exercise alone.
However, other studies have found that fish oil does not appear to affect the type of fuel the body uses during exercise. Thus, more studies are needed before strong conclusions can be made.
Fish Oil: Aiding Fat Loss and Body Reshaping
Even if fish oil omega-3s don't directly lead to weight loss for everyone, they may still contribute to building muscle and reducing body fat. It's important to remember that relying solely on the scale can be misleading, as weight may remain the same even if you're gaining muscle and losing fat. That's why people who want to lose weight are often encouraged to use a tape measure or track their body fat percentages to assess their progress, rather than rely only on the scale.
Using body weight to track loss of body fat may also explain why some studies have failed to find any effect of fish oil omega-3s on weight loss. However, studies that use more precise measurements of fat loss often tell another story. For instance, a study of 44 people reported that those given 4 grams of fish oil per day failed to lose more weight than those given a placebo. However, the fish oil group lost 1.1 more pounds (0.5 kg) of body fat and built 1.1 more pounds (0.5 kg) of muscle than those not given fish oil.
In another study, six healthy adults replaced 6 grams of fat in their diets with 6 grams of fish oil each day for three weeks. They lost no more weight following the fish oil-rich diet, but they did lose more body fat. Similarly, another small study observed that people who took 3 grams of fish oil per day lost 1.3 more pounds (0.6 kg) of fat than those given a placebo. However, participants’ total body weights remained unchanged.
Accordingly, a review of 21 studies concluded that fish oil doesn’t reduce body weight more effectively than a placebo. However, the review showed that fish oil does reduce waist circumference and waist-to-hip ratio more effectively. Thus, fish oil may not help you lose weight per se, but it may make it easier for you to lose inches and help you go down in clothing sizes.
Dosage Recommendations and Safety Considerations
Among the most recent studies that found that fish oil had a positive effect on weight or fat loss, daily dosages of 300-3,000 mg were used. The US Food and Drug Administration (FDA) considers intake of fish oil omega-3s safe if the daily dose does not exceed 3,000 mg per day. However, the European Food Safety Authority (EFSA), the European equivalent of the FDA, considers daily intakes of up to 5,000 mg from supplements to be safe.
It's good to keep in mind that omega-3s have blood-thinning effects that may cause excessive bleeding in some people. If you're taking blood-thinning medication, talk to a healthcare professional before adding fish oil supplements to your diet.
In addition, be careful with the type of fish oil supplements you take. Some may contain vitamin A, which can be toxic when taken in high amounts, especially in pregnant women and young children. Cod liver oil is one example.
And finally, make sure you pay attention to the content of your fish oil supplements. Unfortunately, certain types actually don’t contain much fish oil, EPA or DHA. To avoid these “fake” products, pick a supplement that has been tested by a third party. To get the most benefits from your omega-3 supplements, choose one that is made up of at least 50% EPA and DHA. For instance, it should have at least 500 mg of combined EPA and DHA per 1,000 mg of fish oil.
Choosing a Quality Fish Oil Supplement
When selecting a fish oil supplement, consider the following:
- Third-Party Testing: Opt for products that have undergone independent testing to ensure accurate labeling and purity.
- Vitamin A Content: Avoid cod liver oil due to its potentially harmful high vitamin A levels, especially for pregnant women and children.
- EPA and DHA Concentration: Select supplements with a minimum of 50% combined EPA and DHA content, aiming for at least 500 mg of EPA and DHA per 1000 mg of fish oil.