Brain-derived neurotrophic factor (BDNF) is a fascinating growth hormone that does a lot in our brains.
So what does BDNF do? Quite a bit! It is involved in supporting neurons and neuronal growth in the brain; it also plays a role in long-term memory and in obesity.
Why focus on obesity when everyone knows that fat people are lazy and eat too much? It turns out that our genes may play a larger role in obesity that a lot of people want to concede.
Sidetrack to talk about genetics and weight:
A study of over 10000 twins in the UK found that BMI and waist circumference are highly heritable (77%), with a smaller environmental effect (e.g. sedentary, food choices, sleep) in children.[study] Other, even larger twin studies, have also shown a large genetic component to weight.[study]
So while genetics is undoubtedly involved in obesity, personal choice comes in to play also. Obviously, cutting down on junk food and French fries is important. Instead of blaming genetics, take an active role in learning and understanding the influence and role that it plays in your own personal biochemistry. Then do what you can to fix it.
Back to BDNF and obesity:
Mouse studies have shown that not enough BDNF in the hippocampus causes ‘hyperphagic behavior’, which is a fancy way of saying that they were driven to overeat.[study] (Like when you aren’t really hungry but start munching on some Doritos and then the bag is suddenly half-empty – hyperphagic behavior.) Mouse studies also show that increased or overexpression of BDNF in the hypothalamus increases the conversion of white fat to brown fat. Brown fat increases energy metabolism, and mice with more BDNF stay lean.[study]
Check your 23andMe results for rs6265 (v.4, v.5):
The Met allele (T for 23andMe orientation) causes a decreased in the amount of the active form of BDNF. [study]
The decreased active BDNF due to the Met allele has been linked to a dysregulation of appetite, with lower levels of BDNF tending to cause people to want to overeat.[study] But it isn’t so simple as everyone with the genetic variant having a larger appetite and obesity. The studies on the BDNF variant in obesity haven’t all been conclusive. Some have found that only women with the T allele are at a higher risk for obesity. [study][study] Other studies have found that it also increases the risk of obesity in children in some populations[study] and decreases the risk in other populations[study.] Overall, a meta study that looked at 35 other studies, found that the rs6265 Met allele was associated with obesity. [study]
Other than obesity, the Met allele has also been linked to neuropsychiatric disorders such as depression, bipolar, Alzheimer’s and Parkinson’s. . [study] Other studies have linked the variant to a better response to lithium in bipolar patients, with these patients also improving memory and learning.[study] BDNF levels are also linked to slow-wave sleep, and people with the Met/Met genotype had worse performance on cognitive tasks with sleep deprivation. [study]
Keeping it in perspective: Obviously, not everyone with a BDNF variant is going to have memory issues, Alzheimer’s, bipolar disorder, and obesity. The variants just increases your risk a little bit, which then combines with other genetic variants and your environment. If you are overweight or obese, knowing that BDNF is a genetic factor can give you some tools to target it.
Increasing BDNF levels has been a focus of many studies and there are several things that have been shown to be effective. Mouse studies are simple- just inject BDNF into the hypothalamus and mice reverse obesity and become lean. Humans aren’t mice, and we don’t tend to inject things straight into the hypothalamus. So read through the lifehacks below and see if any of them might benefit you.
Increasing ketone production levels through fasting or a ketogenic diet has been shown in studies to increase BDNF. New to the supplement game are products containing exogenous ketones such as beta-hydroxybutyrate salts that raise your body’s ketone levels. These supplements are often used along with a low-carb diet to kick start ketosis or keep a person in ketosis after eating some carbs. One that I’ve tried is this one on Amazon. There are others available as well, so shop around and read the reviews.
Sleep and light:
In addition to increasing slow wave sleep (talked about above), BDNF is involved in the transmission of light information through the retina to the central circadian rhythm pacemaker (suprachiasmatic nucleus).[study] Good sleep hygiene, including blocking out all light at night with blackout curtains and blocking blue-light in the evening with blue-blocking glasses, is essential. A mouse study found exposure to light at night could cause reduced BDNF expression.[study]
A study of seasonal variations in BDNF concentrations showed that the amount of sunlight a person is exposed to during the week correlates to the level of BDNF.[study]
Lion’s Mane Mushrooms:
Hericium erinaceus, or Lion’s Mane mushrooms, have been used as a traditional Chinese food and medicine for centuries. It is known for its neuroprotective effects. Studies have shown that Lion’s Mane’s effect on depression is through the BDNF pathway.[study] Lion’s mane extract is available in capsules or as a coffee beverage. Personally, I am hooked on Four Sigmatic’s Lion’s Mane and Chaga mushroom coffee. (Please don’t blame me if you try it and then also get hooked on it!)
Exercise increases BDNF:
Getting outside in the sunshine and enjoying a sport or some kind of exercise will increase BDNF levels [study ] Twelve weeks of yoga was also shown to increase BDNF in a randomized controlled trial.[study] Electrically stimulating muscles also increase BDNF in the hippocampus.[study]
BDNF levels naturally fall in the evening [study], so perhaps focusing your exercise time in the morning would be a good idea.
A form of niacin called nicotinamide has been shown in mouse studies to increase BDNF. You can get nicotinamide in capsules or as part of a B-vitamin complex as well as in foods such as nutritional yeast, meats, and milk.
Omega-3 fatty acids were found to increase BDNF levels.[study] A diet high in refined sugars and saturated fats was found to decrease BDNF over a two month period.[study] So eating fish and staying away from junk food should help to increase BDNF.
Coffee fruit extract:
An extract made from the whole coffee fruit (sometimes called coffee cherries) was found to increase BDNF by 143% in human subjects.[study]in
A double-blind, randomized, placebo-controlled trial found that supplementing with 30mg of zinc for 12 weeks increased BDNF levels in depressed subjects.[study]
Stimulating the vagus nerve increased BDNF and reduce weight gain by 25% in a mouse study. [study]
What doesn’t work?
Resveratrol: A study found that 6 months of supplementing with resveratrol actually decreased BDNF and slightly increased weight. [study]
Probiotics: Bifidobacterium longum was not found to modulate anxiety through BDNF changes.[study]
Vitamin D: A placebo-controlled randomized trial found that supplemental vitamin D did not increase BDNF.[study]