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Interest in low-carbohydrate and ketogenic diets continues to rise as people discover their potential to help with stubborn physical health problems, such as obesity and type 2 diabetes—but could this same strategy help with mental health problems as well?
Low-carbohydrate diets have tremendous potential in the prevention and management of psychiatric disorders. The field of nutritional psychiatry is admittedly in its infancy, and rigorous clinical trials exploring the effect of dietary changes on mental health are few and far between, but a tremendous amount of science already exists detailing how high-sugar diets jeopardize brain health, and how low-carbohydrate diets support brain health.
For people with depression, anxiety, bipolar disorder, ADHD, psychotic disorders, PTSD, autism spectrum disorders, and other psychiatric disorders who prefer not to take medication, don’t improve with medication, can’t tolerate or afford medication, only partially benefit from medication, or have bothersome side effects from medication, trying a simple, low-carbohydrate diet (or even a stricter ketogenic diet, particularly in cases of more serious or stubborn chronic symptoms) is well worth trying, with very few exceptions. This statement is based on my study of the science in combination with my clinical experience with patients in the real world.
Low-carbohydrate diets are safe for almost everyone and can lead in many cases to significant improvements in psychiatric symptoms. In my professional opinion, their many potential benefits far outweigh their low risk of side effects. When side effects do occur, they are generally harmless and temporary, although there are clear exceptions.
People currently taking psychiatric medication (or medication of any kind) or who have a history of serious mental health symptoms, such as suicidal ideation, mania, or psychosis, should not embark on a low-carbohydrate diet without additional information and professional support, as medication levels can be affected, and some symptoms may temporarily worsen during the initial weeks of adaptation. If you take psychiatric medication and are considering a low-carbohydrate diet, please read my Psychology Today post, “Ketogenic Diets and Psychiatric Medications,” and consult with your prescribing clinician.
While dietary changes can’t always completely replace medications, they can improve overall health and make good sense as a viable alternative to medication in some cases, or as a complement to conventional care in other cases.
Without further ado, here are eight reasons to try a low-carb or ketogenic diet for mental health:
1. Improve blood glucose control.
The higher your blood sugar, the higher your brain sugar . . . so every time your blood sugar spikes to unhealthy highs, you’re flooding your brain tissue with excess glucose. There are many ways that high glucose levels are toxic to brain cells, including the formation of sticky, dysfunctional proteins called “Advanced Glycation End products” or AGEs. Low-carbohydrate diets are very effective at lowering blood glucose levels. Protect your precious neurons from glucotoxicity.
2. Lower blood insulin levels.
Persistently or repeatedly high insulin levels can cause the insulin receptors on the surface of the blood-brain barrier to become insulin-resistant, meaning they can become damaged, desensitized, and dwindle in number. With fewer healthy, responsive insulin receptors on the surface of the blood-brain barrier to escort insulin into the brain, insulin levels inside the brain will fall. Low brain insulin is dangerous, because brain cells require insulin to process glucose and turn it into energy. This sluggish glucose-processing problem is called “cerebral glucose hypometabolism,” and it is a major risk factor for neurodegenerative disorders like Alzheimer’s and Parkinson’s disease. Low-carbohydrate diets can be very helpful in lowering blood insulin levels. Protect your precious neurons from energy deficits.
3. Reduce inflammation.
High-sugar diets promote excessive, unnecessary inflammation inside the brain, triggering the release of various inflammatory cytokines—tiny SOS signals that recruit first-responder cells to the scene. Inflammation of this type is well established as a root cause of most psychiatric and neurological diseases. Low-carbohydrate diets have been shown to reduce markers of inflammation. Protect your precious neurons from overheating.
4. Boost antioxidant defenses.
High-sugar diets cause excessive, unnecessary oxidative damage. Flooding cells with too much glucose all at once leads to a spilling over of oxygen free radicals, which are normally mopped up by our own natural, internal antioxidant molecules (such as glutathione). Left to run amok, these excess free radicals terrorize the cellular neighborhood, damaging proteins, lipids, DNA, and other important cell components. They can even damage the blood-brain barrier, allowing risky, uninvited guests into the brain. Low-carbohydrate diets naturally help improve your internal antioxidant capacity. Protect your precious neurons from internal attack.
5. Energize mitochondria.
High-sugar diets damage mitochondria, the energy-generating organelles inside brain cells. As a highly metabolically active, electrical organ, the brain is an energy hog, demanding about 20 percent of the body’s energy supply, despite representing only 2 percent of the body’s total weight. Mitochondria must be in tip-top shape at all times to provide cells with a steady supply of high-quality energy. Low-carbohydrate diets—particularly ketogenic diets—have been shown to improve the health and vitality of mitochondria. Protect your mighty mitochondria from power failures.
6. Stabilize stress hormones and appetite.
Refined carbohydrates, like sugar, flour, fruit juice, and processed cereals, place your hormones on an invisible, internal roller coaster. Every time your blood sugar and insulin spike to unnaturally high levels, they soon crash back down, triggering the release of stress hormones, including adrenaline. Adrenaline surges, which can occur four to five hours after consuming too much sugar, can contribute to panicky, “hypoglycemic” symptoms, like anxiety, sweating, shaking, irritability, difficulty concentrating, and carbohydrate cravings. Low-carbohydrate diets help smooth out the highs and lows in blood sugar that lead to hormonal instability in the first place. Protect your precious neurons from hormonal havoc.
7. Rebalance neurotransmitters.
It is a little-known fact that high-sugar diets can wreak havoc with neurotransmitter levels in a number of ways, including through disruptive effects on the kynurenine pathway. The kynurenine pathway helps regulate the activity of serotonin, melatonin, dopamine, GABA, and glutamate—all important neurotransmitters in symptoms of psychiatric disorders. Diets too high in refined carbohydrate promote inflammation and oxidation (see above), which shifts the brain into emergency mode. The kynurenine pathway responds to the alarm by stealing tryptophan away from its serotonin and melatonin synthesis duties to help generate more glutamate instead. As a result, serotonin, melatonin, and GABA activity go down, dopamine activity goes up, and glutamate levels can skyrocket to up to 100 times their baseline levels. You can think of glutamate as the brain’s gas pedal—keeping your foot on this gas pedal for too long too often can cause what is called “glutamate excitotoxicity,” which is very damaging to the brain. Ketogenic diets have been shown to regulate neurotransmitter levels and reduce glutamate toxicity. Protect your precious neurons from glutamate overdrive.
8. Raise BDNF levels.
High-sugar diets can reduce levels of an important molecule called Brain-Derived Neurotrophic Factor. BDNF is a key player in neuroplasticity—in other words, BDNF helps the brain cope with, respond to, and recover from stress. Healthy BDNF levels contribute to resilience—something we all need, as stress is a normal part of life. Low-carbohydrate diets—particularly ketogenic diets—have been shown to raise BDNF levels. Protect your precious neurons by stress-proofing them with BDNF.
If you are curious to learn more about low-carbohydrate diets and mental health, I compiled a library of resources including lots of free videos, articles, podcasts, presentations, and other helpful information.
Note: A low-carbohydrate diet is not the only nutritional strategy worth considering; improving overall dietary quality with a whole-foods pre-agricultural diet (aka “paleo-style” diet) or a whole-foods post-agricultural diet (aka “Mediterranean” diet) may be helpful for some, especially for those without a significant degree of insulin resistance. However, neither of these approaches typically lower insulin and blood glucose levels as reliably as low-carbohydrate diets do.
Most of us have been feeding our brains improperly our entire lives and have no idea how much better we could feel if we ate differently. A whole-foods, low-carbohydrate diet is a safe and healthy option for most people that can help improve brain metabolism, mental health symptoms, and overall health.
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