The carnivore diet, which focuses exclusively on animal products such as meat, fish, and eggs, has gained significant popularity in recent years. Proponents claim it benefits various conditions, including gut health and weight loss, but there are rising concerns about its impact on mental health, especially anxiety.

Have you tried the carnivore diet after seeing headlines like “Carnivore Diet Best for Mental Health,” only to experience adverse reactions such as anxiety, insomnia, or feeling constantly wired? Or perhaps you’re currently on the carnivore diet and have seen significant benefits? Either way, this episode is for you. I’ll offer clarity on the diet’s potential effects on mental health, addressing both positive and negative experiences.

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My goal is to offer a balanced perspective, free from influencer hype, on whether the carnivore diet may be suitable for your mental health. I’ll examine this topic through four key areas:

• Gut dysbiosis and the gut/brain connection
• Imbalanced GABA and glutamate levels in the brain
• The role methylation plays in the consumption of animal proteins
• The impact of oxalate toxicity on the brain and body

Listen to the podcast here:

Links:

• How Oxalate Toxicity Impacts Your Health with Sally K. Norton, MPH
• Glutamine Versus Glutamate: Nutrients and Safety
• MTHFR Methylfolate vs. Folic Acid Facts and Myths

The Gut-Brain Connection: How the Carnivore Diet Affects Digestive Health

So let’s start with one of my favorite topics and a major area of focus in my clinic, the gut/brain connection, and how your gut microbiome plays a huge role in how you tolerate and are able to breakdown and assimilate animal proteins.

Your gut microbiome is a highly intelligent ecosystem of organisms. Bacteria tend to dominate this ecosystem, but you’ve also got viruses, fungi, and protozoan, among other organisms that exist there. Your microbiome is defined as all of these organisms, including their genetic elements.

When the bi-directional connection between the brain and the gut (known as the gut-brain axis) is underdeveloped or the ecosystem becomes imbalanced, you may experience significant anxiety and other mental health challenges. These can include obsessive-compulsive disorder (OCD), depression, and attention-deficit/hyperactivity disorder (ADHD).

The gut is often referred to as the “second brain” for a couple of key reasons. Firstly, many metabolic and neurotransmitter byproducts—including serotonin, dopamine, and GABA—are produced in the gut, significantly influencing brain function. Secondly, the enteric nervous system, a complex neurological network, lines the entire digestive tract.

The enteric nervous system is second only to the brain in terms of nerve endings. In fact, it contains more nerve endings than the spinal cord, making it an incredibly dense neurological tissue. The gut and its bacteria have direct access to the entire nervous system. Moreover, the enteric nervous system is directly connected to the brain via the vagus nerve—also known as the “wandering nerve” due to its path from the brain through organs in the neck, chest, and abdomen.

The vagus nerve serves numerous functions, including facilitating communication between the brain and gut, regulating digestion, respiration, and heart rate, influencing speech and taste sensation, and managing fear responses (fight, flight, freeze). Its wide-ranging roles extend beyond these primary functions.

When the neuronal tissue’s development is impaired, disrupting proper signaling between the gut and brain, the consequences can be far-reaching. These effects may include behavioral disorders, memory issues, slower response times, and difficulties with appetite regulation, mood stability, and sleep patterns.

However, the most common issue is the proliferation of harmful microbes in the gut (a condition known as gut dysbiosis), which significantly impacts the brain. For instance, when opportunistic and pathogenic microbes are allowed to thrive, they produce neurotransmitters in the gut that travel to the brain. This can trigger high anxiety, potentially leading to panic disorders.

Carnivore Diet: Why Results May Vary

When it comes to the carnivore diet, there are two main explanations for why you may or may not respond well to it. The first is that you might have an overgrowth of certain bacteria whose primary fuel source is amino acids—the building blocks of animal proteins.

Take, for instance, the Morganella bacterium. When overgrown, it can cause significant inflammation in the gastrointestinal tract. This gram-negative anaerobic bacteria group is known for producing high levels of histamine in the gut. The effects are twofold: it not only leads to common digestive issues like gas, bloating, nausea, and irregular bowel movements, but also triggers a systemic histamine response. This widespread reaction can manifest in various ways beyond the gut, including anxiety, headaches, nasal congestion, skin problems, and increased heart rate. Interestingly, research has shown a connection between histamine and psoriasis, with studies indicating its involvement in the condition’s pathophysiology.

Additionally, Morganella tends to overgrow when there is digestive dysfunction, such as low levels of stomach hydrochloric acid, pancreatic enzymes, or bile. Consequently, elevated levels of Morganella often occur alongside other histamine producers like Enterococcus, Staphylococcus, and Streptococcus.

Why is digestive dysfunction so problematic on a carnivore diet? Stomach acid is crucial for breaking down proteins into amino acids for digestion and absorption. Hydrochloric acid and bile are antimicrobial, killing bacteria and organisms in food. Pancreatic enzymes are needed to break down proteins, carbs, and fats, supporting stomach acid and bile production.

You’ve probably realized that if you have low stomach acid, you’re not breaking down proteins or digesting them properly, which leads to bacterial overgrowth and an inflamed gut. This issue is exacerbated on a carnivore diet when Morganella levels are high because you’re providing them with their main source of fuel.

Another concern with Morganella is its production of urease, an enzyme that breaks down urea and releases ammonia. Ammonia is particularly toxic to the brain, often resulting in symptoms such as brain fog, anxiety, depression, irritability, low motivation, and difficulty focusing. Excess ammonia can also lead to other issues like psoriasis, insomnia, and muscle twitches.

Similarly, hydrogen sulfide-dominant SIBO renders a carnivore diet unsuitable for individuals with this condition. Hydrogen sulfide gas is primarily produced through protein fermentation in the gut, a process amplified by high protein intake. I’ll delve deeper into this topic in a future episode.

Why might someone with a gut infection respond positively to a carnivore diet? The answer lies in the types of microbes inhabiting the gastrointestinal tract, for example, methanogen overgrowth. This condition, combined with the reduced digestion mentioned earlier, can lead to excessive fermentation of carbohydrates. When bacteria ferment carbohydrates, they produce hydrogen, which most methanogens then use to create methane. Improper food digestion allows gut bacteria to consume and ferment more, resulting in increased hydrogen and methane production.

So to recap, excessive carbohydrate consumption and/or poor carbohydrate digestion can lead to excessive fermentation, resulting in high hydrogen production. Methanogens primarily rely on this hydrogen, produced from carbohydrate fermentation, to generate methane. This process mirrors the Morganella overgrowth scenario, but with carbohydrates as the primary culprit. By eliminating carbohydrates and focusing on animal protein, the carnivore diet effectively removes this trigger.

GABA, Glutamate, and the Carnivore Diet: A Delicate Balance

Let’s delve into GABA and glutamate levels in the brain, which fascinatingly, are also linked to specific gut bacteria. For example, Bifidobacterium and Lactobacillus species produce GABA. Since GABA is the brain’s primary inhibitory neurotransmitter with a calming effect, low levels of these beneficial bacteria may result in decreased GABA production in the gut. This reduction could potentially contribute to a range of issues including anxiety, fear, worry, depression, insomnia, and chronic pain.

This connection to the brain stems from glutamine’s excitatory nature. Glutamine serves as a precursor for both glutamate and GABA, the brain’s primary neurotransmitters. Glutamate, derived from glutamine, is excitatory and potentially neurotoxic. GABA, on the other hand, can counteract excess glutamate. The main concern in the brain is an overabundance of glutamate, which can lead to neurological issues.

As mentioned earlier, GABA has a calming effect on the brain, generally making neurons less hyperactive, while glutamate does the opposite. Brain cells contain numerous glutamate and GABA receptors. When GABA interacts with a neuron at one of these receptors, it alters the cell’s electrical potential, resulting in a calming effect.

L-glutamine, as an oral supplement, is utilized in catabolic states of injury and illness. It’s been employed to fight muscle wasting in individuals with advanced cancer and HIV/AIDS. Professional athletes who expend significant physical energy also use it.

Many people with gut infections and intestinal barrier issues have experienced improvements by using l-glutamine. However, as I mentioned earlier, because glutamine is excitatory, individuals already struggling with anxiety should exercise caution when using it as a supplemental therapy. Although I’ve found l-glutamine supplements to be more problematic than a high-protein diet, similar issues can arise in sensitive individuals who adopt a carnivore way of eating.

For a more in-depth discussion on glutamate, check out Episode 84.

Methylation and the Carnivore Diet

Undermethylation: A Positive Impact

This category is an important one because methylation profoundly impacts the way we think, feel and act, making your dietary choices an important aspect of healing if you have a methylation imbalance.

There are three categories of methylation: under, over and normal.

Undermethylation is a condition that occurs when too few methyl molecules are available to add to enzymes, hormones, and neurotransmitters. When these components don’t function properly, an individual will feel depressed, anxious, and fatigued.

When you lack methyl groups (a carbon group with three hydrogen atoms), your neurotransmitters and hormones suffer. As a result, you’ll likely experience depressed levels of serotonin, dopamine, and norepinephrine. Suboptimal levels of these important neurotransmitters cause depression and anxiety, OCD, perfectionism and ritualistic behaviors, as well as addictive tendencies to name a few.

The reason a high-protein diet such as carnivore is beneficial for undermethylators is that they need the amino acids from animal protein to support the creation of these methyl groups.

Other diets don’t work well because carbohydrates and fats have no effect on methyl production, and vegan and vegetarian diets decrease the presence of methyl in our DNA (due to being very high in folate).

Overmethylation: A Negative Impact

In contrast to undermethylation, overmethylators thrive on a diet lower in protein and higher in folate. This is because they produce an excess of methyl groups. As mentioned earlier, folate helps reduce the presence of methyl in our DNA.

Overmethylation leads to excessive production of the neurotransmitters serotonin, dopamine, and norepinephrine. When you have too many of these neurotransmitters, you’ll likely experience hyperexcitability in the brain. Overmethylation can lead to high anxiety, rumination, an inability to sit still, paranoia, and sleeping problems.

Overmethylators do not respond well to serotonin-enhancing substances such as Prozac, Zoloft, St. John’s Wort, and SAMe, which can make them suicidal. For this reason, a carnivore diet would be inappropriate for these individuals due to the high level of amino acids in animal protein that support the creation of methyl groups in our DNA.

A side note: Keep in mind that genetic tests, such as the highly flawed MTHFR test, cannot determine methylation status. Your methylation status is actually determined by a tug-of-war—as I’ve long maintained—between enzymes for undermethylation and enzymes for overmethylation. Picture eight to ten enzymes on one side versus twelve on the other, working as groups. Whichever side wins this tug-of-war determines your methylation status, not a single enzyme. You may have a SNP (single-nucleotide polymorphism), but that doesn’t necessarily mean it’s causing you any trouble. However, because it’s a genetic test that’s been hyped up by many doctors with huge followings, people assume it must be factual and relevant.

The MTHFR paradigm is neither an accurate assessment nor an appropriate guide for true methylation disorders. The MTHFR test is only 30% expressive at best, meaning 70% is not expressive. Another common misconception is that MTHFR is part of the primary methylation pathway. While MTHFR is a methylating enzyme in a specific part of your system, it’s actually part of the backup pathway, not the primary one.

Methyl groups regulate gene expression by attaching to DNA and influencing whether genes are activated or silenced. This process is affected by various factors, including stress, diet, and pregnancy. Personally, I’m extremely hesitant to base my health decisions on a test with only 30% accuracy and I encourage you to be as well.

Oxalate Toxicity and the Carnivore Diet’s Potential Benefits

Lastly, a compelling reason you may thrive on a carnivore-style diet is due to oxalate toxicity. Oxalate is a naturally occurring compound found in many plants. It’s a tiny molecule that begins as oxalic acid—a two-carbon structure with four oxygen atoms. This composition grants it significant oxidative power. Oxalate also acts as a chelator, eagerly bonding with minerals to form compounds such as calcium oxalate.

A commonly known side effect of oxalate toxicity is kidney stones, but oxalates impact the body across multiple organ systems and are also neurotoxic leading to joint pain, genital and rectal pain, gut problems, anxiety and depression to name a few.

Spinach, almonds, sweet potatoes, and raspberries are all high in oxalates. For individuals sensitive to oxalates, a carnivore-style diet can be a therapeutic option, as it eliminates these problematic foods.

In Episode 46, I had a conversation with Sally Norton about oxalate toxicity and its effects on the body.

Conclusion

In conclusion, it’s crucial to remember that we are all unique individuals, each requiring different nutrients and dietary approaches to thrive. I encourage you to cultivate understanding and compassion for those who may not tolerate the same foods you do.

From a clinical standpoint, I’ve observed that a strict carnivore diet is typically unsustainable for most people in the long-term. However, it can be remarkably beneficial as a short-term intervention while addressing the underlying issues I’ve discussed here.

A diverse diet incorporating healthy animal sources and select plant foods is crucial for optimal health. This variety nourishes beneficial gut bacteria, promoting the production of short-chain fatty acids, hormones, neurotransmitters, and other vital compounds essential for well-being.

Even Dr. Paul Saladino, renowned as “Carnivore MD,” eventually acknowledged that his health significantly declined on a strict carnivore diet. He experienced sleep disturbances, decreased testosterone levels, heightened anxiety, and cognitive impairment, along with other health issues. It wasn’t until he broadened his diet to include fruits, honey, and some dairy products that he regained his health. I have a lot of respect for him coming to this conclusion and being honest about it. Over the years, I’ve discovered that the less dogmatic I am about food, the healthier I am and the better I feel. It’s refreshing to see him embrace this perspective as well.

I believe sharing is caring, so I have a favor to ask. If my show is helpful to you, please share this podcast and consider leaving a review in Apple Podcasts. It is through sharing that we create community, eliminate guilt and shame, and bring about healing. Thank you in advance for taking three minutes out of your day to support my show so others can find me.