Keto And Blood Work: What You Need To Know

The ketogenic ('keto') diet is a popular and effective way to lose weight, but it's important to monitor your health to make sure it's not causing any unintended side effects. Blood tests can help ensure that your body is responding well to the diet, which involves drastically reducing your carbohydrate intake and replacing it with fat. This puts your body into a metabolic state called ketosis, where your liver converts fat into ketones that are used as fuel. While studies have shown that the keto diet may deliver health benefits, it's easy to do it wrong, and it can pose serious health risks that aren't always easy to see. For example, a high-fat diet can increase the amount of 'bad cholesterol' in your system, which can cause atherosclerosis (hardening of the arteries). It can also affect your thyroid hormones and insulin levels, leading to conditions like type 2 diabetes and cardiovascular disease. Therefore, it's recommended to regularly check your blood sugar, cholesterol, and thyroid hormone levels while on the keto diet to safeguard your health.

Blood sugar levels

Blood glucose, or blood sugar, is a primary marker for determining diabetes risk. The higher your blood sugar, the higher your risk factors. However, blood sugar is not just a marker for diabetes. As blood glucose levels rise, so does the risk for many other life-threatening conditions, most notably heart disease.

The best way to mitigate your risk is to keep your blood sugar levels at a normal range. The optimal fasting blood sugar range is likely between 70 mg/dL and 85 mg/dL (3.9 and 4.7 mmol/L). Higher, and diabetes risk goes up. Lower, and you risk a low blood sugar state called hypoglycemia.

The ketogenic diet has the potential to decrease blood glucose levels. It does this by limiting carbohydrates, which turn into sugar and, in large quantities, can cause blood sugar spikes. Instead, the keto diet focuses on fat as the body's primary energy source.

People with type 2 diabetes may benefit from the ketogenic diet, as it can improve blood glucose levels while also reducing the need for insulin. However, the diet does come with risks, and it is important to discuss it with your doctor before making any drastic dietary changes.

When on the keto diet, it is important to monitor your blood sugar levels throughout the day to make sure they are within their target range. This can be done through common tests such as Hemoglobin A1c (HbA1c), OGTT (oral glucose tolerance test), fasting blood glucose, and postprandial blood glucose.

How the Keto Diet Affects Blood Sugar Levels

The keto diet can help to manage blood sugar levels by reducing carbohydrate intake. Carbohydrates have a direct impact on blood glucose. All foods with carbohydrates—whether they are sweet or not—break down into simple sugars in the body, which turn into glucose through metabolic processes. As a result, our blood glucose levels begin to rise.

On the keto diet, the body uses fat for energy instead of carbohydrates or glucose. This helps to minimize the blood sugar response to eating.

Who Should Monitor Their Blood Sugar Levels?

Anyone on the keto diet should consider monitoring their blood sugar levels, especially those with type 2 diabetes. This is because the keto diet can affect blood sugar levels, and it is important to ensure they stay within a healthy range.

Additionally, those with insulin resistance or type 2 diabetes may also benefit from monitoring their blood sugar levels as their bodies are unable to balance blood sugar effectively.

Cholesterol levels

The keto diet is a popular, strict, low-carb, high-fat, and moderate-protein diet. It involves getting 55–80% of your daily calories from fat, 10–20% from protein, and only 5–10% from carbohydrates (20–50g per day).

The keto diet may affect cholesterol levels, but more research is needed to understand the extent of its impact and the circumstances under which it affects cholesterol.

There is conflicting evidence on the impact of keto on cholesterol levels. Some studies suggest that the keto diet can lower levels of high-density lipoprotein (HDL) or "good" cholesterol, while raising levels of low-density lipoprotein (LDL) or "bad" cholesterol. Other studies, however, have found the opposite effect, with HDL levels rising and LDL levels decreasing.

A 24-week study in Kuwait showed that a very-low-carbohydrate ketogenic diet significantly decreased total cholesterol, LDL, and triglyceride levels, while increasing HDL levels. A 2013 review of studies comparing a very low-carb ketogenic diet to a traditional low-fat diet also showed that participants on the keto diet experienced decreases in body weight and diastolic blood pressure, along with increases in both HDL and LDL cholesterol.

The impact of the keto diet on cholesterol levels may depend on the quality of the diet and the types of fats consumed. Unsaturated fats, such as those found in plant oils, fatty fish, nuts, seeds, and avocados, are associated with improved cholesterol levels, especially LDL levels. On the other hand, saturated fats, such as those found in butter, coconut oil, and animal fat, have been linked to poor heart health and increased LDL levels.

Who should be cautious about the keto diet?

The keto diet may not be suitable for everyone, especially those with certain health conditions. If you have high cholesterol, it is important to consult with a healthcare professional before starting the keto diet, as it may impact your cholesterol levels.

The keto diet is also not recommended for people with kidney disease, liver diseases, familial hypercholesterolemia (high cholesterol levels inherited from family), or fat-induced lipemia, as it may worsen these conditions.

Additionally, people with a rare genetic condition that affects how LDL particles are regulated should avoid the keto diet, as it can cause their LDL levels to skyrocket. This condition is called familial hypercholesterolemia (FH) and is marked by very high LDL levels and an increased risk of premature heart disease. Only about 10% of people with FH are aware that they have it, so it is important to consider your family history and consult with a healthcare provider before starting the keto diet.

How to follow a heart-healthy keto diet:

If you decide to follow the keto diet, it is important to focus on consuming heart-healthy, unsaturated fats instead of saturated fats. Choose foods such as nuts, nut butter, seeds, avocado, and extra virgin oils like olive oil. Maximize the small number of carbohydrates allowed by including non-starchy fruits and vegetables like avocados, tomatoes, asparagus, broccoli, and spinach.

It is also important to be under the care of a healthcare provider while following the keto diet to ensure that it is safe and healthy for you. Get your cholesterol levels tested before and during the diet to monitor for any unsafe changes.

In summary, while the keto diet may offer some benefits, such as weight loss and improved cholesterol levels for some people, it is not suitable for everyone. It is important to consult with a healthcare professional and consider your individual health history before starting the keto diet, especially if you have high cholesterol or other health conditions.

Thyroid hormones

The thyroid is a small gland located at the base of your neck, which plays a huge role in the development of your body and the maintenance of your metabolism. It secretes two hormones into your bloodstream: T4 (tetraiodothyronine) and T3 (triiodothyronine). T4 is the inactive form of T3 and is converted to T3 as needed. T3 is the biologically active hormone that plays a role in the metabolism of all your cells and manages functions such as the speed of digestion.

Research indicates that periods of starvation (which the keto diet mimics) and weight loss from the keto diet can lower T3 levels, leading to weight gain. When your body perceives a 'famine', your metabolism downregulates to become as efficient as possible to keep you alive for as long as possible. Lower T3 means less energy expenditure.

Additionally, the keto diet can put you in a 'fight or flight' state, which is bad news for your thyroid. When you don't consume carbs, your body has to figure out how to make carbs to sustain blood sugar, relying heavily on stress hormones such as cortisol and adrenaline. Cortisol is responsible for increasing gluconeogenesis in the liver, a process that makes carbs from protein and fat. Research shows that people with hypothyroidism tend to have higher levels of stress hormones, to begin with, and the keto diet can make these levels even higher.

Furthermore, the keto diet may lead to decreased thyroid hormone production, increased inflammation, potential micronutrient deficiencies, and elevated cortisol levels. Carbohydrates are needed to make thyroid hormones work, and a very low-carb diet may result in decreased thyroid hormone production.

In summary, while the keto diet may offer benefits such as weight loss and improved blood sugar control, it can also negatively impact thyroid hormone levels and increase stress hormones. If you have a thyroid condition, it is essential to consult with a healthcare professional before starting the keto diet.

Triglycerides

The ketogenic diet is a low-carb, high-fat eating plan that puts the body into a metabolic state called ketosis. In ketosis, the body uses fat, not glucose from carbohydrates, as its main energy source. This shift impacts lipid metabolism, the process by which the body breaks down fats like triglycerides to create energy.

The ketogenic diet's influence on triglycerides is twofold. Firstly, by reducing carbohydrate intake, the body has less need to store excess energy as triglycerides. Secondly, the process of ketosis itself focuses on fat burning, which includes the usage of stored triglycerides.

Several clinical studies have shown the potential of the ketogenic diet to lower triglyceride levels. For example, a study published in the Journal of Nutrition and Metabolism found significant reductions in triglyceride levels among participants following a ketogenic diet.

The type and quality of fats consumed on the ketogenic diet also play a role in determining triglyceride levels. Foods like avocados, nuts, seeds, and fish contain healthy fats such as monounsaturated and polyunsaturated fats, which help maintain balanced triglyceride levels. On the other hand, a high intake of saturated and trans fats can potentially increase triglyceride levels.

People with elevated triglycerides who start a ketogenic diet will almost always see a reduction in their triglyceride levels. Those with metabolic syndrome can see their serum triglycerides reduced by half on average. However, increases in triglycerides while on a ketogenic diet can rarely occur, usually due to a high intake of carbohydrates or alcohol.

Reduced triglyceride levels can lead to various health benefits. Lower triglycerides contribute to a healthier heart and a reduced risk of cardiovascular diseases. When combined with the potential weight loss and improved blood sugar control often seen on the ketogenic diet, these benefits can significantly enhance overall health.

Inflammatory markers

Inflammation is a key part of the body's ability to heal itself and protect itself from illness and other damage. However, too much inflammation can have serious consequences, including chronic diseases. The ketogenic diet is anti-inflammatory, and many people are turning to it to help manage and reduce symptoms from inflammation.

Being in ketosis means the body is using fat instead of sugar for energy. Excess sugar causes the body to produce high amounts of insulin, raise inflammation markers, and trigger chronic disease. Eating a ketogenic diet that is very low in sugar helps halt the surges of insulin from unregulated sugar levels that raise blood sugar and create inflammation in the body.

The ketones your body produces when you start burning fat instead of sugar are powerful, anti-inflammatory agents. The weight loss associated with this switch can also lead to a reduction in inflammation markers in the body.

The ketogenic diet has been shown to have a beneficial effect on inflammatory markers and CVD risk factors. This is due to the anti-inflammatory properties of the state of ketosis, the elimination of simple sugars, the restriction of total carbohydrates, and the supply of omega-3 fatty acids.

The main ketone body, beta-hydroxybutyrate, exhibits a number of anti-inflammatory properties, including mimicking the fasting state. It has multifaceted effects, including influencing gene expression, reducing inflammation, and improving mitochondrial function. Beta-hydroxybutyrate can block the NLRP3 inflammasome, an immune system receptor linked to inflammation.

The ketogenic diet has been shown to have a positive effect on inflammatory markers and CVD risk factors. However, there is a lack of strong evidence of the CVD risk from dyslipidemia due to the ketogenic diet.

Frequently asked questions