This is Your Brain on Food
Psychiatrist, chef, and author of This is Your Brain on Food, Uma Naidoo, MD, explains what to eat to improve cognitive function, mood, energy, concentration, and libido, and highlights key supplements.
Scientifically reviewed by Dr. Gary Gonzalez, MD, on November 2021. Written By Uma Naidoo, MD.
Food has a profound effect on mental health. It impacts your risk of depression, brain fog, and Alzheimer’s, and plays a role in libido, sleep, OCD, and much more.
In This is Your Brian on Food, board-certified psychiatrist, nutrition specialist, and professionally trained chef Uma Naidoo reveals cutting-edge research on the direct connection between the gut and the brain.
Naidoo says that because many doctors overlook this connection, they are missing a key component to successful treatment and recovery.
“Until we solve nutritional problems, no amount of medication and psychotherapy is going to be able to stem the tide of mental issues in our society,” said Naidoo.
In this book, Naidoo explains how you can use diet to achieve well-being in every aspect of your mental health. She offers practical advice on what to eat (and what not to eat) to improve your cognitive function, mood, energy, concentration, libido, and more.
She also highlights key nutrients and supplements that help build the foundation of healthy brain function.
In this interview with Life Extension Dr. Naidoo explains the critical gut/brain connection, and offers practical tips to help with depression, memory, sleep problems, and more.
LE: How does food influence your brain?
Dr. Naidoo: Food influences your brain directly and indirectly. When food is broken down by the microbiota into fermented and digested materials, its components directly influence neurotransmitters such as serotonin, dopamine, and GABA, which travel to the brain and change the way you think and feel.
When food is broken down, its constituent parts can also pass through the gut wall into the bloodstream, and certain metabolites can act on the brain that way as well.
Food’s most profound effect on the brain is through its impact on your gut bacteria. Some foods promote the growth of helpful bacteria, while others inhibit this growth.
Because of that effect, food is some of the most potent mental health medicine available, with dietary interventions sometimes achieving similar results to specifically engineered pharmaceuticals, at a fraction of the price and with few, if any, side effects.
On the other hand, food can also made you sad—certain food groups and eating patterns can have a negative effect on your gut microbiome and your mental health.
The idea of using food as medicine for mental health is central to nutritional psychiatry, and in my opinion, it’s crucial to finding meaningful, lasting solutions to mental health problems.
Until we solve nutritional problems, no amount of medication and psychotherapy is going to be able to stem the tide of mental issues in our society.
LE: How can something as basic and natural as eating be as potent as a drug that cost millions of dollars to develop and test?
Dr. Naidoo: The primary reason gut bacteria have such a profound effect on mental health is that they are responsible for making many of the brain chemicals.
If normal gut bacteria are not present, production of neurotransmitters such as dopamine, serotonin, glutamate, and gamma-aminobutyric acid (GABA)—all critically important for the regulation of mood, memory, and attention—is impacted.
Many psychiatric disorders are rooted in deficits and imbalances of these chemicals, and many psychiatric drugs are tasked with manipulating their levels.
Therefore, if your gut bacteria are intimately involved with producing these vital chemicals, it stands to reason that when your gut bacteria are altered, you risk doing damage to this complex web of body and brain function.
That’s a lot of responsibility for a group of microscopic organisms!
LE: Does this mean that your diet can impact your risk of depression?
Dr. Naidoo: When discussing depression and the gut with my patients, I often use the phrase “blue bowel,” a lighthearted name for the very serious relationship between depression and your gut.
Food changes the types of bacteria present in your gut microbiome. Your gut bacteria may become less diverse as a result of your diet, which may cause the bad bacteria to outgrow the good bacteria, triggering a cascade of negative health effects.
Studies in humans appear to confirm this hypothesis. In 2019, psychiatrist Stephanie Cheung and her colleagues summarized findings from six studies that looked at gut health in patients with depression.
They reported that patients with major depressive disorder had at least 50 types of bacterial species in their gut microbiome that were different from those of control subjects without major depressive disorder.
Recent research suggests that bacterial species associated with higher quality‑of‑life indicators are depleted in depressed subjects, while bacteria that cause inflammation are often found in higher numbers in people suffering from depression.
This tells us that inflammation and depression are closely linked.
LE: If you’re suffering from gut-induced depression, how do you reset your gut microbiome to help achieve a healthy mental state?
Dr. Naidoo: The key is to increase probiotics and prebiotics in your diet. Probiotics are live bacteria that convey health benefits when eaten. Probiotic-rich foods contain beneficial bacteria that help your body and brain.
In 2010, Michael Messaoudi and his colleagues studied 55 healthy men and women who were randomly assigned to receive either a daily probiotic formula or a placebo for 30 days.
Compared to the placebo group, those in the probiotic group reported less depression, and urinary levels of cortisol (the body’s main stress hormone) were lower, indicating that their brains were less depressed and less stressed.
Why was this the case? Certain species of gut bacteria have the ability to boost levels of brain chemicals such as gamma-aminobutyric acid, which may speed relief from depression and other mental health conditions.
Magnesium is also important for proper brain function. Countless studies have suggested that depression is related to magnesium deficiency. Several case studies, in which patients were treated with 125-300 mg of magnesium, have demonstrated rapid recovery from major depression, often in less than a week.
LE: Another issue people struggle with as they get older is memory. Why is the typical Western diet so bad for memory?
Dr. Naidoo: High-fat and high-glycemic-index (high‑GI) foods can alter brain pathways necessary for learning and memory, with neurons in the hippocampus and prefrontal cortex especially affected.
The hippocampus is the part of the brain most involved in forming relational memories.
High-fat and high‑GI diets can affect the hippocampus in a variety of ways. First, the Western diet can hamper the expression of critical growth factors like brain-derived neurotrophic factor and other hormones that promote healthy function in the hippocampus.
Second, poor diets can affect insulin signaling and insulin sensitivity in the body’s tissues. It’s unclear exactly what insulin’s role is in the hippocampus, but studies have indicated that it likely impacts memory.
One recent study showed that high saturated fat intake in male rats interfered with insulin signaling in the hippocampus, which led to interference with hippocampal function and corresponding relational memory abilities.
Third, a diet high in saturated fat and refined sugar in male rats showed increased oxidative stress, which damages brain cells and reduces the efficacy of cell‑to‑cell communication in the hippocampus.
Dietary components such as saturated fat may also exacerbate inflammation in the brain, which has been linked to cognitive decline in aging and risk of developing Alzheimer’s disease.
Inflammation disrupts many of the chemical pathways instrumental in memory formation, such as those that rely on dopamine and glutamate. The nerves themselves become sluggish and information travels far more slowly.
LE: Besides cutting out high-fat and high-GI foods, what nutrients can someone take to improve memory?
Dr. Naidoo: Curcumin has antioxidant, anti-inflammatory, and neurotrophic activities. In fact, one recent review of 32 animal and laboratory studies showed that it can reverse some brain damage caused by Alzheimer’s.
A 2019 review of curcumin studies also showed improvement in attention, overall cognition, and memory.
Another is saffron. In 2010, Shahin Akhondzadeh and his colleagues tested whether saffron could impact cognition. They administered either 15 mg capsules of saffron or a placebo twice daily to people with mild to moderate Alzheimer’s disease. After 16 weeks, saffron produced a significantly better outcome on cognitive function than placebo.
LE: Many of our readers struggle with getting adequate sleep. How can you eat for better sleep?
Dr. Naidoo: The best recipe for sleep often lines up with a healthy diet. For example, in 2014, Ryoko Katagiri and her colleagues reported that women who ate more noodles and sweets and less vegetables and fish had worse sleep than those with healthier diets.
Broadly speaking, I recommend you follow a healthy, whole-foods diet like the Mediterranean eating pattern, and make sure to include or exclude certain foods based on how they affect your sleep.
LE: What is one specific nutrient that’s been proven to help improve sleep?
Dr. Naidoo: You can add improved sleep to the long list of benefits of omega‑3 polyunsaturated fatty acids. A number of studies in animals demonstrate that omega‑3s decrease inflammation and normalize sleep, and that they protect the brain from memory impairment in sleep-deprived mice.
There are also an increasing number of studies that demonstrate the beneficial effects of omega‑3s on human sleep.
For instance, in 2018 Leila Jahangard and her colleagues conducted a study on 50 depressed patients. Compared to those on a placebo, the participants who received omega‑3s improved their depression, anxiety, and emotional control, and over time they improved their sleep as well.
LE: What are some ways to help clear up brain fog?
Dr. Naidoo: “Brain fog” occurs when you cannot think clearly, when you cannot concentrate or multitask, or when you lose short-term and long-term memory.
In 2015, Theoharis Theoharides and his colleagues showed that luteolin, a type of flavonoid, has numerous neuroprotective properties that decrease brain fog. As an antioxidant and anti-inflammatory agent, this substance prevents toxic destruction of nerve cells in the brain.
In 2018, Lucy Harper and her colleague Justine Bold showed that gluten can cause brain fog. After consuming gluten, some people find themselves thinking less clearly and wanting to sleep all day. If you are suffering from brain fog, cut out gluten to see if you improve. It may turn out that you have celiac disease or non-celiac gluten sensitivity.
Phosphatidylserine (PS) is required for healthy nerve cell membranes and coverings, and its protective effects can prevent brain fog. In 2010, Akito Kato-Kataoka explained that six months of soybean-derived PS improved memory function in elderly Japanese adults.
LE: What are your thoughts on taking drugs to treat mental health issues?
Dr. Naidoo: Modern mental health medications can be a godsend to patients who struggle with a variety of disorders, and I don’t want to downplay their importance as a therapy in many circumstances.
But what sometimes gets lost in discussions about mental health is a simple truth: the food you eat can have just as profound an effect on your brain as the drugs you take.
It’s important to work with a mental health professional to develop the right mix of psychotherapy and antidepressant medication when necessary. But no matter what, the food you eat will be an important part of the puzzle.
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