Ketogenic Versus Plantogenic: Which Provides the Most Benefit?

As I have discussed in numerous posts, plant-based diets have certain health and environment benefits that animal-based diets do not. Plant-based diets are of numerous types such as vegetarian, lacto-ovo vegetarian, lactovegetarian, ovo-vegetarian, pescetarian, vegan, and raw vegan.

CAN PLANT-BASED DIETS SUSTAIN PROTEIN NUTRITION?

IS THERE A CORRELATION BETWEEN PLANT VERSUS ANIMAL DIETS AND MORTALITY?

PLANT VERSUS ANIMAL PROTEIN: IS IT COMPOSITION OR TOTAL PROTEIN THAT MAKES THE DIFFERENCE

Despite the numerous health benefits of plant-based diets, strict vegan diets are associated with risks for vitamin and mineral deficiency. The most likely deficiency with a strict vegan diet vitamin B12, which is predominantly obtained from animal sources. A long-term deficiency of vitamin B12 is the primary cause of macrocytic anemia and can also result in neuropsychological effects. Vegan diets are also limiting in the important omega-3 fatty acids, eicosapentaenoic acid (EPH) and docosahexaenoic acid (DHA). Therefore, it is imperative that vegans supplement a strict plant-based diet with sources of vitamin B12 (only reliable means is consumption of B12 fortified foods or B12 supplements) and EPA and DHA (e.g. algae such as spirulina).

Although most information indicates that consumption of plants rich in alpha-linolenic acid (ALA), such as flaxseed or flaxseed oil or chia seeds, is an effective way to acquire EPA and DHA, the ability of the human body to convert ALA to EPA is limiting and further conversion to DHA is even more limiting. The activity of both the delta-5-desaturase (D5D, encoded by the FADS1 gene) and delta-6-desaturase (D6D, encoded by the FADS2 gene) enzymes that are required for ALA conversion to EPA and DHA is slow and can be further compromised due to nutritional deficiencies as well as during inflammatory conditions. In healthy females only around 20% of dietary ALA is converted to EPA and less than 10% is converted to DHA. In healthy males only around 8% of ALA is converted to EPA and there is no appreciable conversion to DHA. The rate of EPA and DHA conversion from ALA is reduced by up to 40% when ALA is consumed along with pro-inflammatory omega-6 fatty acids, such as the essential fatty acid linoleic acid and arachidonic acid. In addition, the consumption of alcohol has been shown to reduce the level of DHA in the liver and the blood. In addition, hyperglycemia and hypercholesterolemia are both known to interfere with the activity of D5D and D6D.

Additional dietary deficiencies that have been associated with strict vegan diets are zinc, iron, calcium, vitamin D, and iodine. Also, whereas certain foods such as sugar, sugar sweetened foods, sugar-sweetened beverages, potatoes, and rice are classified as plant-based foods, consumption of these foods is associated with higher weight gain and, consequently, to a higher incidence of diabetes and other chronic diseases.

Ketogenic diets are those in which the amount of carbohydrate consumed is low to very low and the amount of fat consumed is high. The deficiency in carbohydrate reduces the availability of glucose which is the primary energy molecule of all cells. The high levels of fatty acids, along with reduced carbohydrates, leads to the increased production of the ketones, beta-hydroxybutyrate (BHB) and acetoacetate, via the oxidation of the fatty acids. The ketones are utilized by various tissues (excluding red blood cells), particularly the brain and the heart, for energy production. Ketogeneic diets were originally devised in the 1920's for the treatment of epilepsy. These diets are now highly popular for weight loss. Caution is necessary with adherence to ketogenic diets since high levels of ketones in the blood (ketonemia) leads to potentially severe and life threatening metabolic acidosis. Also, high levels of ketones in the urine (ketonuria) results in excessive loss of water resulting in dehydration.

Ketogenic diets have been clearly shown to assist in weight loss particularly in the first 3 to 6 months of adherence to this type of diet. Ketogenic diets are also associated with improved blood lipid profiles that in turn can lead to reduced risk for cardiovascular disease. In addition, the consumption of a ketogenic diet by individuals who are obese and have type 2 diabetes improves glucose control and systemic insulin sensitivity. Despite the short-term benefits of a ketogenic diet, studies have found that long-term weight loss with the ketogenic diet might not be achieved. Indeed long-term studies have not shown any difference in weight loss between ketogenic diets and other forms of weight control diets. Additionally, the lack of nutrient-rich foods (such as fruits, vegetables and grains) in a typical ketogenic diet can result in nutritional deficiencies. Also, with the main caloric intake in ketogenic diets being fats there actually is the likelihood for increased risk for cardiovascular disease. This is indicated by the increase in low-density lipoprotein (LDL) seen in long-term ketogenic diets. Ketogenic diets are also typically deficient in adequate fiber contributing to constipation and, more importantly, a reduction in beneficial bacteria in the gut. Beneficial bacteria contribute to ones overall health by providing nutrients, aiding a robust gut immune system, and enhancing the gut-brain axis that regulates feeding behaviors.

One of the primary benefits of plant-based diets is weight loss but they are also better for the environment. In addtion, plant-based diets are rich in fiber. High-fiber diets have been shown to reduce constipation and to prevent colon cancer and several other intestinal pathologies. The consumption of a diet containing 29 grams or more of fiber on a daily basis has been found to be associated with a decrease in the risk of colon cancer, diabetes, heart disease, and strokes. Fiber consumption levels represent one of the significant differences between plant-based diets and ketogenic diets. The beneficial bacteria propagated in the gut with high fiber generate short-chain fatty acids, SCFA (acetate, propionate, and butyrate) which are absorbed by colonocytes. Metabolically the gut bacteria-derived SCFA can be used for oxidation or diverted into the ketogenesis pathway. In addition to hepatocytes, gut epithelial cells are the only other cell to express the HMGCS2 gene (encoding mitochondrial HMG-CoA synthase) allowing them to contribute to ketone synthesis. However, gut-derived SCFA also exert other important cell signaling effects.

Although the beneficial effects of these SCFA can be attributed to all three, the most extensively studied effects are those exerted by butyrate. Butyrate promotes colonocyte cell differentiation, suppresses colonic inflammation, and of clinical significance it induces cell cycle arrest and apoptosis in colon cancer cells. These beneficial effects of butyrate (and also shown for propionate), within the colon are mediated, in part, by its ability to inhibit the activity of histone deacetylases (HDAC). Like butyrate, the ketone beta-hydroxybutyrate (BHB) has also been shown to inhibit the activity of HDAC. The effects of beta-hydroxybutyrate-mediated HDAC inhibition are enhanced expression of genes that reduce the level of oxidative stress. Plant-based diets are also rich in antioxidant chemicals that protect one from chronic diseases such as heart disease and diabetes. The combined role of plant-based diets in gut-based control of inflammation and the effects of the antioxidants in plants has been shown to associated with a reduced risk of cancers such as mouth, larynx, pharynx, esophagus, stomach, lung, bladder, and breast.

TAKE HOME: If the appropriate attention is paid to the acquisition of EPA, DHA, and vitamin B12 even the strictest of plant-based diets, veganism, is the healthiest choice and the safest for long term environmental considerations.