A ‘Metabolic Switch’ May Explain Why Fasting Boosts Gut Health

Fasting for 24 hours can reverse the loss of stem cell function in the gut that accompanies aging, according to a study of mice.
Intestinal stem cells are crucial for tissue repair and regeneration, and their decline as we age means that it becomes harder to recover from gastrointestinal conditions and infections.

The researchers, who were led by a team from Massachusetts Institute of Technology (MIT) in Boston, discovered that fasting for 24 hours boosted regeneration of gut stem cells in younger and older mice. They found that fasting exerted this effect by means of a metabolic switch that causes cells to break down fatty acids instead of carbohydrates such as glucose. They also discovered a molecule that can activate the same switch – a finding that might lead to drugs that boost older people’s recovery from gastrointestinal infections or chemotherapy.

Stem cells are immature cells that have remarkable properties. For instance, they can replicate almost indefinitely and develop into virtually any type of cell in the body, forming an essential source of new cells for growth and repair in many tissues. In the gut, they maintain and repair tissue lining, which ‘renews itself’ about every 5 days.

Now published in the journal Cell Stem Cell, co-senior author Omer H. Yilmaz – an assistant professor of biology at MIT – explains that diet is known to have a “profound effect” on the ability of tissue to regenerate itself. There is also evidence that intermittent fasting can benefit health and age-related decline in tissue function.

Wisdom Wednesday: The Atkins Diet

The thrust of the Atkins Nutritional Approach is to significantly reduce one’s carbohydrate (carbs) intake. The craze for low carbs comes mainly from the popularity of the Atkins’ books. The Atkins diet is a four-phase eating program, combined with vitamin and mineral supplements, as well as regular exercise.

Dr. Atkins said the main factor that causes us to put on weight is our consumption of refined carbs, especially sugar, high-fructose corn syrup, and flour.

The goal of the diet is to force the body into ketosis. In ketosis the metabolism switches from burning glucose as fuel to burning its own stored body fat. When glucose levels are low and our insulin levels are low, ketosis kicks in as the body switches to stored fat as a source of energy.

Phase 1: Induction
Calorie consumption from carbs is limited to 20 grams per day. Carb sources are mainly from salad and low starch vegetables. The urine is monitored with a “keto-stick” for ketosis. The is the most difficult portion of the diet but it lasts only two weeks.

Phase 2: OWL (Ongoing Weight loss)
Nutrient-dense and fiber rich foods are added as additional carb sources, at an increased rate of 25 grams during the first week of this phase, 30 grams during the second week, and 30 grams for each subsequent week until your weight stops going down. At that point – when weight loss stops – you take away 5 grams of carbs from your daily intake until you are starting to lose weight slowly.

Phase 3: Pre-Maintenance
Increase your carb intake by 10 grams each week until your weight loss is very gradual.

Phase 4: Lifetime Maintenance
Start adding a wider range of carb sources, while carefully monitoring your weight does not go up. Your sense of well-being must continue. If your weight starts to go up, ease back on two things – the amount of carbs you consume each day, and any of the new carbs you have been introducing. Dr. Atkins says that “this lifestyle is the foundation for a lifetime of better health”.