Keto Diet and Immune System: What You Need to Know

We all know that different diets can have an impact on our waistline, but did you know certain diets can also influence your immune system?

The ketogenic diet is one such eating pattern, with research showing that it may have the potential to reduce inflammation, help with viral infections, alter the gut microbiome, and more. That said, it's not the easiest diet plan to follow, and not all of its influence is positive.

Let's find out more about it and discuss what you need to know about the keto diet and immune system.

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Introduction to the Ketogenic Diet

The ketogenic diet or keto diet is a high fat and low carbohydrate diet. And when we’re talking low carbs, we mean very low carbs!

Don’t confuse this diet with a generic low carb diet, because the latter typically still involves more carbohydrates than are allowed on keto.

There isn’t just one version of the keto diet so it’s a little hard to give exact recommended macronutrient intakes, but a typical keto diet restricts carbohydrate intake to less than 50g a day. Some versions state 30g a day.

Protein is also kept fairly moderate compared to other low carb diets as it can kick you out of ketosis, the desired result of the keto diet. However, it is important to ensure adequate protein to maintain nutritional balance and support metabolic processes while on a ketogenic diet.

A typical ketogenic diet, therefore, may look something like the below.

A typical keto diet includes:

• 5-10% carbohydrates

• 10-20% protein

• 70-80% fat.

Why so few carbs? Because people following a keto diet want to alter the way their body produces and uses energy. They want to enter a metabolic state called ketosis.

What is Ketosis?

Here’s what normally happens when you eat carbs - and what happens when you restrict them on the keto diet:

1. When you eat carbohydrates such as sugars or starchy foods, the body breaks them down into glucose, the body’s preferred source of energy.

2. If you don’t need the glucose immediately, it is stored in the liver and muscles as glycogen, ready for future use.

3. When you restrict your carbs and glycogen stores drop, the body will burn stored fat for energy instead. During this process, stored fat is broken down into fatty acids, which are then used as an energy source.

4. This metabolic state is known as ketosis. Acids called ketones - a by-product of ketosis - build up in the blood and can be used as alternate fuel sources by most tissues in the body, including the brain.

Why do keto dieters want this? Mainly for weight loss. But there are other potential benefits to a keto diet, including an influence on your immune system. (1-4)

Health Benefits of a Keto Diet

It’s probably fair to say that while the diet was originally developed for people with epilepsy back in 1921, most people now follow a ketogenic diet for weight loss reasons.

However, studies have also suggested a ketogenic diet may offer several other health benefits. Such as:

• A ketogenic diet can potentially reduce inflammation

• According to meta studies, a low carb keto diet has shown promise for longer term weight loss than a low fat diet. (5) Notably, participants in these studies often vary in body mass index (BMI), which can influence the observed outcomes.

• The keto diet has also shown positive effects on glycemic control, insulin resistance, and lipid markers.

• A 2004 study showed the keto diet significantly reduced weight, body mass index, and LDL or ‘bad’ cholesterol among obese participants over 24 weeks. All risk factors for heart disease. A small number of other studies have mimicked this fall in bad cholesterol.

IN CONTRAST: While studies generally agree that a keto diet can help you lose weight, at least in the short term, they don't all agree that it can reduce LDL cholesterol. In fact, in many studies the opposite is true.

They have seen LDL cholesterol rise. This may be because of the exact make-up of the diet - the type of fats eaten, for instance. Or it may be that a keto diet helps to reduce LDL cholesterol in certain groups of people, but not all. (6-9)

The Ketogenic Diet and the Immune System

Here’s what we really want to know from this article - can a ketogenic diet influence our immune system? And how? Positively, or negatively?

Research has shown that distinct immune responses are triggered by different dietary interventions, such as vegan and ketogenic diets.

It turns out that a keto diet can both help and hinder different elements of the human immune system. Various immune cells, including T cells, B cells, and others, appear to be influenced by a keto diet, highlighting the complexity of immune modulation by diet.

Before we get into this subject in depth, however, allow me to give you a brief Immune System 101.

Immune System 101

We all know the immune system acts as the body’s defense system, protecting us from germs, viruses, bacteria and more. We may not know, however, just what that entails - and that several organs and elements support or make up the immune system.

We’re talking bone marrow, the spleen, lymphatic system and many more - plus white blood cells, antibodies, immune cells etc…

For our purposes here today, however, we really need to know that there are two ‘sections’ or subsystems of the immune system with specialized roles that together form a distinct immune system:

1. Innate immune system (non-specific) - this is the first part of the immune system to respond to invaders, reacting in the same way to all. It includes a range of specialized white blood cells, such as Natural Killer (NK) cells.

2. Adaptive immune system (specific) - this is the part of the immune system that produces antibodies, that recognises or ‘remembers’ pathogens or harmful substances the body has seen before. You might hear this referred to as the ‘acquired’ or learned immune response. This includes T and B cells, as well as antibodies.

The innate immune system responds first, while adaptive immunity is slower but tends to be more accurate because it has the power to ‘remember’ germs. This is the reason that you may become ‘immune’ to certain illnesses once you’ve had them once in your life. (11)

Why is this important? Because studies show that a keto diet has the potential power to influence your adaptive immunity.

Let’s examine that…

Keto Diet 'Rewired Adaptive Immune System' in Two Weeks

A small study published in Nature magazine examined more than one diet, specifically comparing vegan and ketogenic diets, and claimed that a ketogenic diet positively ‘rewired’ the adaptive immune system in a fortnight.

Scientists closely monitored participants' immune responses and metabolic changes throughout the study.

"Our data revealed that overall, a ketogenic diet was associated with a significant upregulation of pathways and enrichment in cells associated with the adaptive immune system" - study authors. (12)

If you’re interested, a vegan diet in contrast showed potential influence on the innate immune system.

It should be noted that this study involved just 20 people, so further wider research is welcome.

The Keto Diet and Viral Infection

These findings followed earlier reports that the ketogenic diet increased γδ T cells (gamma delta T cells, a sub-section of T cells) responses in mice. This expansion of γδ T cells in the lungs aided anti-viral protection, and was shown to protect mice against the Influenza A virus.

What was particularly interesting about this research is that the authors showed that just providing ketone bodies (bypass ketogenesis) or following a general high-fat/high-carb diet didn’t give the same protection. Suggesting that the metabolic adaptation from a true ketogenic diet is important. (13, 14)

Other animal studies have shown that being in ketosis or giving ketone bodies helped the animals handle viral or brain-related infections better. For example, in mice with herpes-related infections, ketosis reduced how sick they became, and it also changed how their immune cells (like T cells) behaved. (15)

Let's look at T-cells in a bit more detail...

A Ketogenic Diet Strengthens T Cell Immune Responses

Researchers put healthy adults on a very low-carb diet (similar to keto) and looked at how their immune cells behaved. They found that when your body switches to burning fat and making ketones, your T cells - the immune cells that fight viruses and help coordinate your whole immune system - actually work better.

These changes are part of broader cellular processes linked to immune cell activation and function.

All of which suggests they would be better at defending you. (16)

Ketones May Reduce Inflammation

I mentioned earlier that a keto diet may reduce inflammation. That’s because ketones have anti-inflammatory benefits and can potentially modulate the inflammatory response in the brain and elsewhere.

Chronic inflammation is a major driver behind many chronic diseases and immune-related disorders. Chronic inflammatory diseases and neurological diseases, such as Alzheimer's, Parkinson's, and multiple sclerosis, are often characterized by persistent neuroinflammation.

By shifting the body’s metabolism, keto diets decrease the production of pro-inflammatory cytokines like TNF-α and IL-6, while boosting anti-inflammatory molecules such as transforming growth factor β (TGF-β). This anti-inflammatory effect not only supports enhanced immunity but may also lower the risk of infectious diseases and chronic inflammatory conditions.

Keto Diet Alters the Gut Microbiome

The gut microbiome in our intestines is home to trillions of bacteria and microorganisms that help digest our food, produce essential vitamins, protect against harmful microbes - and support the immune system.

70% of our immune cells are located in our gut, so this is an important aspect of our immunity. The gut microbiome communicates with the Central Nervous System to help regulate immune responses.

The impact of a ketogenic diet on our gut microbiome is complex. We can't just say it is positive or negative; it's much more nuanced than that.

For instance:

CONTEXT MATTERS: In epilepsy and some neuroinflammatory models, however, a keto diet and microbiome changes may be beneficial. Ketones are believed to confer anticonvulsant benefits, and may protect against seizures, though the exact mechanism is still being debated.

For this reason, a therapeutic ketogenic diet may be recommended by doctors in patients with drug-resistant epilepsy. (24)

In short, a keto diet may offer anti-seizure and/ or neuroprotective benefits, but in otherwise healthy adults, it may carry gut-health trade-offs.

You can support your gut microbiome by...

1. Preserving non-starchy vegetables, nuts, seeds, and low-carb fibrous foods in your diet.

2. Taking a quality prebiotic (though be careful that its fiber content doesn't kick you out of ketosis). A prebiotic like Performance Lab Prebiotic with Inulin-FOS, for instance, may help to boost levels of Bifidobacterium in your gut and offers a 2g dose via three Nutricaps a day.

   This allows you to decide how many capsules you want to take. When on a keto diet, it's advisable to start with 1-2g of prebiotic a day, and to test and keep track of your ketones.

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How MCT Oil can Help

MCT oils are specifically well-suited for ketogenic diets.

Performance Lab’ MCT Energy Oil, for instance, is made from pure C8 and C10 medium-chain triglycerides (“good MCTs”). These are absorbed quickly and sent to your liver, where they’re efficiently converted into ketones - the fuel your body uses on a keto diet instead of glucose.

Because of this, taking this MCT oil gives you a fast, clean source of energy. It can help support your brain (better focus, reduced “keto brain fog”), boost your metabolism, and help you stay in ketosis or deepen it.

Finally, because it’s ultra-pure (organic coconuts, no additives) and mostly C8/C10, it’s less likely to cause digestive issues than lower-quality MCT oils, making it an attractive option to include in your keto routine.

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Limitations of the Keto Diet

For all of the promising research, there are some limitations and potential drawbacks of the keto diet. Some of these may be mitigated by the use of a quality MCT oil, such as Performance Lab MCT Energy Oil.

They are:

1. It’s a Major Lifestyle Commitment. Yes, guidelines are clear but there is little flexibility and it may be tough to sustain it long term.

2. Lack of Research. Most research into a ketogenic diet examines its short term impact and has either been carried out on animals, done in a lab setting or includes just small groups of human participants. More longer term research is needed to recreate the potential benefits of keto with more people from diverse backgrounds.

3. Testing your ketones is the only sure way to determine if you are in ketosis, and this requires a testing kit.

4. The diet is not suitable for anyone who has a history of disordered eating.

5. You may experience ‘keto flu’ when first trying the keto diet. More on that below…

Keto Flu

While a ketogenic diet may have its benefits, initial entry into ketosis can have some side effects as your body adjusts to the new normal. These side effects, known as the Keto Flu, are usually mild and short-term, but they can still be unpleasant.

You may experience headaches, nausea, fatigue, brain fog, dizziness, insomnia or more, but symptoms usually resolve in a few days to a few weeks.

Using a quality MCT oil may help reduce keto symptoms by providing a quick energy source and helping to speed up time to ketosis. We recommend Performance Lab MCT Energy Oil.

It usually takes around 72 hours for the body to enter ketosis.

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Keto Warnings

As I mentioned above, more research needs to be done on the health impact of following a long-term keto diet.

Potential complications could include kidney stones, low blood pressure, nutrient deficiencies, electrolyte imbalances, digestive issues, muscle loss, and an increased risk of heart disease, the latter potentially depending on the type of fat you eat.

The diet is not recommended for anyone who has conditions or problems with the thyroid, gallbladder, liver or pancreas. Anyone with diabetes should first see a doctor before trying the ketogenic diet as complications may occur if medication is not appropriately adjusted. (27)

Final Thoughts

The central nervous system is deeply intertwined with the immune system, and the ketogenic diet offers a unique way to influence both.

Keto diets tend to boost adaptive immunity, increasing T cell activity and reducing inflammatory pathways. Its ability to modulate immune response means it has been considered as a therapeutic nutritional intervention for several health conditions.

Before you consider a ketogenic diet, however, you should do your research and make sure you still eat healthily, avoiding too many saturated fats and choosing appropriate foods to limit any damage to your gut microbiome.

As I mentioned, a quality prebiotic like Performance Lab Prebiotic may help with this by encouraging beneficial bacteria.

A top notch MCT oil is also a good idea. It can potentially help you enter ketosis quicker and - hopefully - reduce the side effects of the keto flu. We recommend Performance Lab MCT Energy Oil.