Well, if you watch the Dr. Oz Show, you may have heard him call raspberry ketones “The #1 miracle in a bottle to burn your fat.” Since he made that bold statement, I’ve heard that raspberry ketone supplements are being sold so fast that vitamin stores can’t keep them long enough on the shelves!
So, what I’d like to do is review the raspberry ketone research — minus the hype that you have already heard about it. Only in this way can you make an informed decision about whether raspberry ketone is right for you or not.
Other names for this supplement include red raspberry ketone, and European red raspberry, as well as the more scientific names Rubus idaeus, Rubus strigosus and Framboise Rouge.
What are raspberry ketones?
Red raspberry ketones are one of many compounds in raspberries and are what gives raspberries their unique smell. Like all things that come from fruits and vegetables, raspberries contain a lot of substances that are healthy —including anthocyanins, vitamin C and beta carotene. As such, raspberry ketones are also antioxidants.
Few weight loss supplements that contain raspberry ketones include QuickTrim — the Kim Kardashian supplement —and Apidexin.
Raspberry ketones also “look” similar to synephrine and capsicum — two ingredients that have been used in many weight loss supplements over the years such as the fat burner promoted by Jillian Michaels.
This similarity is likely why scientists considered raspberry ketones as a weight loss agent itself.
Around 2010, scientists noticed that raspberry ketone had a similar molecular structure to capsaicin, which is the chemical responsible for the heat in chili peppers.
Preliminary studies also suggested that capsaicin prevents weight gain. In light of these findings, scientists ran studies in mice and on human tissue to see if raspberry ketone also influences weight gain.
In a study published in 2005, called the Anti Obesity Action of Raspberry Ketone, raspberry ketones were given to mice that were fed a high-fat diet for several weeks. Mice were split into different groups, each getting the same calories but getting different amounts of raspberry ketones (0.5%, 1% or 2%).
The diets were about 40% fats in each group. Researchers noted that raspberry ketones — that made up between 1% and 2% of total calories — caused a reduction in body weight and fat buildup in the livers of mice after 10 weeks of use, compared to mice that were only fed a high-fat diet.
Norepinephrine (also called nor-adrenaline) is a chemical made in the adrenal glands that acts as a neuro transmitter and does many things, one of which includes helping to burn fat. This study also incubated isolated mouse fat cells in norepinephrine along with raspberry ketones to see what would happen.
The researchers observed that the combination of raspberry ketones and norepinephrine caused more fat to leave the fat cells than norepinephrine alone.
This is why Dr. Oz said raspberry ketones cause fat cells to shrink. I’m telling you this because various websites claim that raspberry ketones increase levels of norepinephrine. However, this study did not show that.
Rather, the researches only showed that raspberry ketones appeared to improve the fat-burning ability of norepinephrine. This is actually a good thing because too much norepinephrine can be bad. For example norepinephrine can raise blood pressure.
Oddly, this study noted that while a 1% intake of raspberry ketones tended to raise triglyceride levels in the mice, eating it at a concentration of 5% of total calories tended to reduce triglycerides.
These researchers also quoted previous studies noting that raspberry ketones raised metabolic rates—in rats. That’s interesting, but where’s the proof that raspberry ketone raise metabolism in people?
So this was just a mouse study —and a small study at that! Each group only had 6 mice.
In this study, published in 2010, researchers found that red raspberry ketones inhibited weight gain and improved fat burning in mice that were fed a high fat diet. Researchers also noted that raspberry ketones increase levels of adiponectin, a hormone made in fat cells.
The Wikipedia page on adiponectin goes into more detail, discussing how the hormone does a variety of things including improving the sensitivity of insulin— (good for diabetics).
Dr. Oz said that Adiponectin was the “hormone that tricks the body into thinking it’s thin.”
When we put on weight, we reduce the ability of the adiponectin hormone to work. Sounds good, but red raspberries have only been shown to reduce adiponectin in mice.
What about people? Have raspberry ketone supplements been proven to help people lose weight by raising adiponectin levels?
Tip. There is more evidence that exercise raises adiponectin levels than for raspberry ketones —and exercise has been shown to work in people!
Norepinephrine and Adiponectin
When researchers took isolated fat cells from rats and made them grow in a test tube, adding raspberry ketones to the mix had two effects:-
• It increased lipolysis (breakdown of fat), primarily by making the cells more sensitive to the effects of the fat burning hormone norepinephrine.
• It made the fat cells release more of the hormone adiponectin.
Adiponectin is a hormone that is released by fat cells and is believed to play a role in regulating metabolism and blood sugar levels. Thin people have much higher levels of adiponectin than people who are overweight and the levels of the hormone increase when people lose weight. Studies have shown that people with low adiponectin levels are at a higher risk of obesity, type 2 diabetes, fatty liver and even heart disease.
Therefore, it stands to reason that raising adiponectin levels with natural means could help people lose weight and lower the risk of many diseases.
How much raspberry ketone do you need?
If raspberry ketones help people lose weight, what dosage works? Nobody knows because there are no human studies of raspberry ketones and weight loss.
If we believe the mouse studies (which I don’t), it appears that a concentration of 1% of total calorie intake might help weight loss. If that is correct, then the amount of raspberry ketones needed would be different for different calorie intakes.
For example, a person who consumes 1800 calories per day would need less than a person who eats 2000 calories per day.
Do raspberry ketones suppress appetite?
Various websites make the claim that raspberry ketone supplements can reduce appetite. But I see no proof of this. Even the mouse studies I cited above, do not state that raspberry ketone supplements suppress appetite.
Before believing that raspberry ketone supplements can stop people from eating too much, ask the makers of those products for “published peer reviewed proof in humans”.
Anti-aging effects of raspberry ketones
Can raspberry ketone supplements slow down the aging process? Do they reduce wrinkles? Well, red raspberry ketones do have some antioxidant effects but it’s a long shot to go from that to saying that they are “anti-aging.”
Raspberry ketones may be found in some cosmetics because they seem to have a skin whitening effect —at least in skins of mice. That’s fine, but I recommend you save your money from raspberry ketone anti-aging supplements as they are not an “anti-aging super food.”
For those who really want a “super food,” eat raspberries! Here’s why: antioxidants work best in small amounts and when they are eaten in combination with the other ingredients in food. Because of this fact, raspberries are better than raspberry ketone supplements when it comes to being healthy.
Raspberry ketone is not well studied as concentrations used in supplements – which can range from 50 to 250 milligram per serving. And there are some known side effects from their use.
“Raspberry ketone may lower blood sugar levels, and decrease the risk of bleeding,” Dr. Ulbricht said.
So, people taking drugs for diabetes should be monitored closely by their healthcare team. R
aspberry ketone may also cause changes in body fat and weight, changes in inflammation, heart palpitations and shakiness.
Raspberry ketone may also interfere with medicines, such as those that regulate heart rate, cholesterol and hormones.
“There is currently not enough reliable safety information on the use of raspberry ketone in humans,” Ulbricht said.