Vertical Sleeve Gastrectomy VSG and Changes in the BrainJuly 21, 2021
How Does the VSG and Changes in the Brain Occur? Obesity not only affects metabolic health but also affects brain function and structure. Changes in the brain activity such as cognitive function (decrease memory capabilities, learning absorption) and brain atrophy have been seen in individuals with obesity. The treatment of obesity with bariatric surgery has been shown to improve obesity-related cognitive impairment and brain function.
Vertical Sleeve Gastrectomy & Changes in the Brain
The Vertical Sleeve Gastrectomy (VSG) (also known as the Laparoscopic Sleeve Gastrectomy (LSG) has gained popularity as a result of its safety and low complication rate, making it particularly suitable for people with severe obesity and comorbidities.
The VSG is classified as a mechanical restrictive and metabolic procedure because it involves complex physiological changes. Both restriction and hormonal modulation achieve weight loss through the modification of the gastric fundus. The gastric fundus expresses various hormones associated with hunger and satiety, insulin secretion, and energy balance and is known to induce rates of type 2 diabetes remission comparable to those observed following malabsorptive procedures.
The biological mediators that support cognitive control and long-term weight loss after the VSG remain unclear. However, VSG helps to reduce cravings for high-calorie meals, ghrelin, insulin, and leptin levels and increased self-reported cognitive-control of eating behavior.
The effects of the gut-brain axis on the central nervous system result in fluctuating hormone transmission from your GI tract to your brain.
People with obesity have shown functional abnormalities in the frontal-limbic regions of the brain. The frontal lobe, like all brain regions, connects with the limbic lobe, which houses brain structures associated with the limbic system. The limbic system controls automatic and primitive reactions, but these reactions are heavily dependent upon emotion and experience.
VSG significantly decreased BMI, craving for high-calorie food cues, ghrelin, insulin, and leptin levels, and increased self-reported cognitive-control of eating behavior. Leptin and ghrelin are hormones that are known to have a prominent role in the relationship between hunger and satiety.
How the Vertical Sleeve Gastrectomy Works and Benefits
The "hunger" hormone ghrelin regulates food intake and preference for high-calorie (HC) food through modulation of the mesocortico-limbic dopaminergic pathway. Most ghrelin-producing cells are in the fundus. Ghrelin also plays a role in determining how much of what we eat is burned for fuel versus stored as fat.
Weight loss alone results in an increase in ghrelin, which explains why we tend to feel hungry as soon as we restrict calories and begin to shed pounds.
Surgically induced weight loss, however, in which a portion of the stomach is removed or bypassed, reduces the production of ghrelin while restricting the volume of food consumed. This unique combination explains, at least in part, why bariatric patients are able to eat less but not feel hungrier as a result.
Ghrelin travels through your bloodstream and to your brain, where it tells your brain to become hungry and seek out food. Ghrelin's main function is to increase appetite.
VSG-induced reductions in appetite and total ghrelin levels in the blood are associated with reduced prefrontal brain reactivity to food cues. Leptin also plays an important role in telling your body when you are full and how calories are stored.
It is believed that weight loss improves the body’s sensitivity to the messages leptin delivers to the gut and brain. This, in turn may result in greater food satisfaction with smaller quantities and less flavor intensity.
So how does this change in food cues affect weight loss? If you preferred sweets or salty foods before you had surgery and crave them less after surgery, you are more likely to stick to healthier foods in general. That's the good news.
However, some of our patients still crave unhealthy fatty foods after surgery. That makes it harder to keep off the weight. Reduction in craving for high-calorie food cues has been shown to continue 6 to 12 months after VSG. Additional research has shown evidence that VSG improved functional and structural connectivity in prefrontal regions of the brain, which contribute to enhanced cognitive control and sustained weight loss following surgery.
VSG and Changes in the Brain: Take-Aways
In conclusion, it is likely to experience taste bud changes after undergoing VSG. This is most commonly due to the sensory changes occurring as a result of fluctuating hormones in the gut-brain axis affecting the central nervous system. Basically, your nervous system relays countless transmissions about your hunger, satiety, and cravings each day between your GI tract and your brain.
Because the carriers of these messages are affected by changes in weight and the removal of a portion of the stomach, it is highly likely they have an impact on taste, smell, gratification, and other sensory perceptions. The good news is that patients who have changes in taste buds and food cues tend to lose more weight than those who do not experience this effect.
In addition, studies have shown that increased weight reduction diminishes food cravings and excess hormone storage in fat cells. It’s important to remember that food aversions after VSG are not permanent; therefore, weight loss optimization should be focused on in the first year of surgery.
Dr. Patricia Cherasard is the Chief Physician Assistant
for Winthrop Surgical Associates and Bariatric Surgery
ABOUT THE AUTHORDr. Patricia Cherasard is the Chief Physician Assistant for Winthrop Surgical Associates and Bariatric Surgery at NYU Health's NYU Winthrop Hospital. Her role in the perioperative period of our bariatric surgical patient population includes guidance in the preparation for weight loss surgery, helping to attain their weight loss goals, and maintenance of their weight loss as well as improved health outcomes.
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