Keto Diet: Friend Or Foe Of Bone Mass Density?

The ketogenic diet is a low-carb, high-fat diet that is often used for weight loss and the treatment of epilepsy. While the diet has been shown to be effective for these purposes, its impact on bone health is less clear.

Some studies have suggested that the ketogenic diet may negatively affect bone health, particularly in athletes and children with epilepsy. For example, one study found that elite race walkers who followed a ketogenic diet for 3.5 weeks had increased levels of a bone resorption marker and decreased levels of bone formation markers. Another study found that children with epilepsy who were on the ketogenic diet had lower bone mineral density than less-active children.

However, other studies have shown no significant changes in bone mass density or bone health in people following a ketogenic diet. Additionally, it is important to note that no human studies have been conducted with powerful and adequate experimental designs to definitively determine the impact of the ketogenic diet on bone health.

Overall, while there may be some concerns about the potential effects of the ketogenic diet on bone health, particularly in certain populations, more research is needed to fully understand the relationship between the ketogenic diet and bone mass density.

Ketogenic diets may cause a steady rate of bone loss

A study on elite race walkers found that a ketogenic diet increased post-exercise levels of CTX, a marker of bone resorption, compared to a high-carb diet. It also decreased levels of P1NP and OC, markers of bone formation and metabolism. However, this study did not examine bone mineral density, and had a small sample size of only 30 people.

Another study on children with epilepsy found that active children had lower bone mineral density on a ketogenic diet compared to less active children. However, this may be due to the use of anti-epileptic drugs, which are known to decrease bone mineral density.

In general, there is a lack of human clinical studies with powerful and adequate experimental designs to definitively determine the impact of ketogenic diets on bone health.

Ketogenic diets may lead to a chronic acidotic state

Ketogenic diets are very restrictive and can lead to inadequate intake of essential vitamins, minerals, and phytochemicals. They are typically low in fiber, vitamins, and minerals such as thiamin, folate, vitamin A, vitamin E, vitamin B6, calcium, magnesium, iron, and potassium.

Ketogenic diets are also associated with an increased risk of kidney stones, which is a common side effect in children placed on ketogenic diets. This is due to the diet's emphasis on high-fat, animal-based foods while excluding many fruits and vegetables. The acidosis caused by the ketogenic diet may also encourage stone formation by lowering urinary citrate and pH levels while increasing urinary calcium levels.

Ketogenic diets may cause growth stunting

The ketogenic diet has been linked to growth stunting in children, with some studies reporting a decrease in height and weight in those following the diet. This could be due to the diet's high fat content, which can cause occasional food refusal, or the body being put into a "chronic acidotic state" due to high levels of ketones. However, other studies have found that the ketogenic diet does not negatively impact growth, and in some cases, may even improve it.

The Ketogenic Diet and Growth

The ketogenic diet is a high-fat, low-carbohydrate diet that has been used to treat drug-resistant epilepsy and glucose transporter type 1 deficiency syndrome. While the diet has been found to be effective in treating these conditions, there are concerns about its potential impact on growth, particularly in children.

Some studies have found that the ketogenic diet can lead to growth stunting. For example, a study by Williams et al. (2002) reported a significant decrease in height and weight percentiles in children following the ketogenic diet for two years. Similarly, Peterson et al. (2005) found that children with high levels of ketones in their urine had lower height z-scores than those with moderate ketosis. This suggests that the high levels of ketones produced by the ketogenic diet may have a negative impact on growth.

However, other studies have found no evidence of growth stunting in children following the ketogenic diet. For example, a study by Liu et al. (2003) found no significant changes in height or weight in children on the ketogenic diet for up to two years. Similarly, a retrospective study by Ferraris et al. (2019) found that most children (80%) treated with the ketogenic diet for 12 months did not show growth retardation.

Potential Mechanisms for Growth Stunting

There are several potential mechanisms by which the ketogenic diet may cause growth stunting. One factor may be the high fat content of the diet, which can make it unpalatable and lead to occasional food refusal, resulting in inadequate calorie intake. Additionally, the ketogenic diet can cause a chronic systemic reduction in pH, or acidosis, which is known to impair growth. The high levels of ketones produced by the diet may also affect endocrine pathways regulating growth.

Factors Influencing Growth on the Ketogenic Diet

Several factors may influence whether children following the ketogenic diet experience growth stunting. These include the age at which the diet is started, with younger children being more likely to grow poorly on the diet. The underlying medical condition being treated may also play a role, as children with epilepsy may show suboptimal growth patterns due to endocrine dysfunction or the use of multiple anti-epileptic drugs. Additionally, inadequate calorie or protein intake compared to recommended values may contribute to growth stunting.

While there is some evidence to suggest that the ketogenic diet may cause growth stunting, particularly in children, the findings are inconclusive. Further research is needed to identify the children most at risk of poor growth on the ketogenic diet and to clarify the potential mechanisms underlying growth stunting.

Ketogenic diets may increase the risk of kidney stones

Kidney stones are a well-documented potential side effect of the ketogenic diet. Research has shown that among children following the keto diet as a treatment for epilepsy, 13 out of 195 subjects developed kidney stones.

The ketogenic diet can be particularly dangerous for people with kidney disease, as they often need to follow a low-protein diet, which may not align with the type of keto diet they are following.

The ketogenic diet is extremely restrictive and very difficult to stick to. It involves reducing carbohydrate intake to less than 50 grams per day and increasing protein and fat intake. This means that a single baked potato or slice of bread could constitute an entire day's worth of carbohydrates.

The ketogenic diet may also cause an increased risk of kidney stones and gout, as it can lead to higher levels of calcium and uric acid in the body. This is due to the diet's high intake of animal proteins, which can make urine more acidic.

However, it is important to note that kidney stones are rare during a well-formulated ketogenic diet, and the risk of developing kidney stones may be mitigated by ensuring adequate hydration and including plenty of green vegetables, nuts, and seeds in the diet.

Ketogenic diets may cause pancreatitis

The ketogenic diet has been gaining attention as a potentially effective method for weight control and management of type 2 diabetes. However, there have been rare reports of serious side effects, including pancreatitis.

Case Study: 35-Year-Old Man

A 35-year-old man presented to the emergency department with weekly abdominal pain on Monday mornings, following "cheat days" on the weekend, during which he consumed more carbohydrates relative to his calorie-restricted ketogenic diet. The patient was diagnosed with acute pancreatitis, with no associated alcohol use, hypertriglyceridemia, pancreatic obstruction, or other anatomical abnormalities.

The patient's symptoms resolved with conservative management and progressive reintroduction of a standard diet. This case suggests that the ketogenic diet may lower the threshold for acute pancreatitis and that an episodic stressor, such as a "cheat day", may trigger an acute attack in the absence of traditional risk factors.

Other Cases

There have been several other reports of acute pancreatitis associated with the use of a ketogenic diet. In one case, a patient with pre-existing hypertriglyceridemia developed acute pancreatitis after starting a ketogenic diet. In another case, a 9-year-old girl with a rare genetic disorder developed pancreatitis while on a ketogenic diet.

Mechanism

The proposed mechanism for the development of pancreatitis in individuals on a ketogenic diet is related to the high-fat content of the diet. A single high-fat meal can cause a spike in triglycerides in the bloodstream, which can increase the risk of inflammation of the pancreas.

While the ketogenic diet may be effective for weight control and management of type 2 diabetes, there is a potential risk of developing pancreatitis, particularly with episodic high-fat intake. Further studies are needed to fully understand the relationship between the ketogenic diet and pancreatitis.

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