Nih Ketogenic Diet
The ketogenic diet remains a valuable therapeutic option for patients with intractable epilepsy. Clinical aspects of the diet’s success may provide insights into epileptogenesis and anticonvulsant action. The diet’s efficacy has been established primarily through large case series. The diet has been used successfully in patients with many different epilepsy syndromes in countries around the world. Potential adverse effects can be avoided with careful attention during the diet’s initiation and maintenance phases. In the last decade, variations to the classical ketogenic diet have been utilized. Ketogenic diets now are being used for diseases other than epilepsy. This critical analysis of the diet should provide the impetus for further clinical and basic research into the diet’s application and mechanisms of action.
Benefits and adverse effects of ketogenic diets
The ketogenic diet was originally developed in 1924 to treat epilepsy, but other, more recently discovered benefits include weight loss and reversal/control of type 2 diabetes. Use of ketogenic diets in weight management has gained tremendous popularity, but it has also generated several controversies. Some researchers suggest that there are no metabolic advantages with low carbohydrate diets and that weight loss results simply from reduced caloric intake, probably due to the increased satiety effect of protein. However, the majority of ad libitum studies demonstrate that individuals who follow a low-carbohydrate diet lose more weight during the first 3-6 months compared with those who follow more balanced diets.
Besides a positive effect on weight loss, studies have shown that low-carbohydrate ketogenic diets also reduce serum triglycerides dramatically. Elevated serum triglycerides are common among Asian Indians, and this is one of the features of the so-called Asian Indian Phenotype. Reduction in total cholesterol and increase in high-density lipoprotein cholesterol have also been reported. A key enzyme in cholesterol biosynthesis is 3-hydroxy-3-methylglutaryl-CoA reductase, which is activated by insulin. This means that an increase in blood glucose and consequently of insulin levels will lead to increased endogenous cholesterol synthesis. A reduction in dietary carbohydrate will thus have the opposite effect and this, coupled with the additional inhibition by dietary cholesterol and fats on endogenous synthesis, is likely to be the mechanism by which physiological ketosis can improve lipid profiles.
Thus, low-carbohydrate ketogenic diets have been shown to have immense benefits in blood sugar control. There are some reported beneficial effects on cancer and neurological disorders such as Alzheimer’s disease and epilepsy although these are not discussed further here as it is beyond the purview of this article.
However, there are also several adverse effects of ketogenic diets. These include muscle cramps, bad breath, changes in bowel habits, keto-flu and loss of energy. Hence, monitoring individuals on keto-diet closely once or twice a month for blood glucose, ketones cardiac and other parameters is essential.
Should ketogenic diets be recommended?
Indian diets are very high in carbohydrates. The STARCH study has shown that Indians with or without diabetes consume at least 65 per cent calories from carbohydrates. The Chennai Urban Rural Epidemiology Study (CURES) has also shown that carbohydrate constitutes the major source of calories in south India. We also know that India has a huge burden of type 2 diabetes and cardiovascular disease. Data from the PURE study showed that high carbohydrate intake (more than about 60% of calories) was associated with an adverse impact on total mortality and non-cardiovascular disease mortality. By contrast, higher fat intake was associated with lower risk of total mortality, non-cardiovascular disease mortality and stroke. In contrast, in a recent study on dietary carbohydrate and mortality, Seidelmann et al showed that there existed a U-shaped relationship between carbohydrate intake and mortality. Both extremely high (60% and above) and low carbohydrate diets (<30% carbs) were shown to have higher mortality rates. The risk of dying was lowest when the carbohydrate intake was between 50 and 55 per cent. Moreover, mortality rates were lower when the dietary carbohydrates were replaced by plant-based proteins and fats but higher in those who were on animal-based proteins and fats.
One of the challenges of low-carbohydrate diets is that these have a lower intake of vegetables, fruits and grains and increased intakes of fat which can be detrimental. Long-term low-carbohydrate diets with increased fat consumption have been hypothesized to stimulate inflammatory pathways, oxidative stress and promote biological ageing.
The biggest problem with extreme diets like keto diets is their sustainability. In our experience, people are initially thrilled with the weight loss and the excellent diabetes control they get, after using keto diets. Slowly, however, they get bored with the diet. Furthermore, many feel weak and frustrated and start increasing the carbohydrate intake, and soon they are back to their original weight and diabetes control. Recent studies also suggest that ketogenic diets may, in fact, induce hepatic insulin resistance. There are also reports of micronutrient deficiency and cardiovascular safety. Hence, many more studies need to be done before these diets are widely recommended.
