Brain-derived neurotrophic factor (BDNF) is a fascinating growth hormone that has many functions in our brain. It is involved in supporting neurons and neuronal growth in the brain; it also plays a role in long-term memory and in obesity.
Weight and waist circumference are referred to by researchers as ‘highly heritable’. This means that genetics – along with diet and lifestyle – plays a big role in your propensity to gain weight.[ref] [ref]
So why are we talking about the brain and BDNF when it comes to your weight? When genetics researchers looked at the genes that are linked to gaining weight, several of the genes are involved in the way that your brain controls your appetite. This makes sense when you think about it. If you are driven by your brain to eat more – even if it is just a little more each day – you will eventually gain weight. Your appetite control center is in the brain, and genetics points to several mechanisms here.
Animal studies show that not enough BDNF in the hippocampus causes ‘hyperphagic behavior’, which is a fancy way of saying that they were driven to overeat.[ref]
Mouse studies also show that increased or over-expression of BDNF in the hypothalamus increases the conversion of white fat to brown fat. Brown fat increases overall energy metabolism, and mice with more BDNF stay lean.[ref]
This holds true in human research as well – lower BDNF levels are linked to higher appetite and increased food consumption.
Check your genetic data for rs6265 (23andMe v4, v5; AncestryDNA):
The Met allele (T ) causes a decreased amount of the active form of BDNF. [ref]
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.[ref]
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. [ref][ref] Other studies have found that it also increases the risk of obesity in children in some populations[ref] and decreases the risk in other populations[ref.] The difference may be lifestyle factors, such as the amount of time spent outdoors, being active.
Even though some small studies have shown contradictory results, a meta study that combined the data from 35 other studies found that the rs6265 Met allele was associated with obesity. [ref]
Research shows that there are several ways of naturally increasing BDNF levels.
Sleep and sunlight:
BDNF increases slow wave sleep and is involved in the transmission of light information through the retina to the central circadian rhythm pacemaker (suprachiasmatic nucleus).[ref] Animal studies show that exposure to light at night reduces BDNF expression.[ref]
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 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.[ref] Lion’s mane extract is available in capsules or as a coffee beverage.
Exercise increases BDNF:
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.
Niacin (vitamin B3):
A form of niacin called nicotinamide has been shown in mouse studies to increase BDNF. You can get nicotinamide as a supplement or through niacin-rich foods such as nutritional yeast, meats, and milk.
Omega-3 fatty acids have been shown in studies increase BDNF levels.[ref]
A diet high in refined sugars and saturated fats was found to decrease BDNF over a two month period.[ref]
A double-blind, randomized, placebo-controlled trial found that supplementing with 30mg of zinc for 12 weeks increased BDNF levels in depressed subjects.[ref]
Stimulating the vagus nerve increased BDNF and reduce weight gain by 25% in a mouse study. [ref]
What doesn’t work to increase BDNF?