What are the effects of weight loss on natural killer cell function, our first line of immune defense against cancer, as well as kidney function and fatty liver disease?
The Effects of Obesity on the Immune System and Kidney and Liver Diseases
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In the ABCs of the health consequences of obesity, I is for Immunity.
The SOS trial, which followed the fates of thousands of bariatric surgery patients for a decade or two (compared to a control group that maintained their weight, and those who surgically lost about 20 percent of their body weight, not only lived longer, thanks in part to less diabetes and less cardiovascular disease, but they also got less cancer. This may be because anti-tumor immunity appears to be affected by weight. Natural killer cells are your immune system’s first line of defense against cancer cells (as well as many viral infections), and their function is severely impaired in obesity. Randomize obese individuals to a weight-loss program, though, and there was a significant reactivation of their natural killer cell function within just three months. The program involved an exercise component, though, and so it’s hard to tease out the impact of the weight loss itself, since physical activity alone can boost natural killer cell activity.
On the other end of the immune spectrum, obesity is suspected to be a causal risk factor for the development of the autoimmune disease multiple sclerosis. This suggests obesity is associated with the worst of both worlds when it comes to immune function: underactivity when it comes to protecting against cancer and infection, but overactivity when it comes to certain inflammatory autoimmune conditions.
J is for Jaundice. Thanks to the obesity epidemic, nonalcoholic fatty liver disease is now the most common liver disorder in the industrialized world. Fat doesn’t just end up in our belly and thighs, but inside some of our internal organs. More than 80 percent of individuals with abdominal obesity may have fatty infiltration into their liver, and in those with severe obesity, the prevalence can exceed 90 percent. This can lead to inflammation, scarring, and ultimately, cirrhosis and liver cancer. Currently, this nonalcoholic fatty hepatitis is the leading cause of liver transplants in American women, and men are expected to catch up in 2020.
K is for Kidneys. Obesity is also one of the strongest risk factors for chronic kidney diseases. Your kidneys compensate for the metabolic demands of the excess weight by red-lining into what’s called “hyperfiltration” to deal with the extra workload. This resulting increased pressure within the kidneys can damage the sensitive structures, and increase the risk of kidney failure over the long term.
What about L, M, N, O, P through Z? If you want to continue through the alphabet, the L could be for diminished lung function, M for metabolic syndrome, and so on…. There’s even an X—for xiphodynia—pain at the tip of the bottom of the breastbone from being bent forward by an expanding abdomen.
Given the myriad of health conditions associated with excess weight, annual medical spending attributable to obesity is nearly $2,000 per year, with obese workers with multiple conditions costing companies up to $10,000 more in healthcare coverage, compared to lean counterparts. This may actually account for some of the wage gap that obese employees experience, as companies try to pass along these costs beyond just brazen discrimination. Between healthcare costs and diminished productivity in terms of lost workdays, the total lifetime costs of obesity for children and teens has been estimated to exceed $150,000.
Some estimates peg the national cost of obesity at about $150 billion dollars, with another $50 billion per year added by 2030 as our increasingly heavy baby boomers continue to age. Others diametrically disagree, based on the morbid fact that obese individuals may not live as long. Just as the medical costs of tobacco-related diseases may be more than offset by the shortened survival of smokers, the lifetime healthcare costs of obese individuals may turn out to be lower because they are expected to die so much sooner. So, the true cost may be more in lives, rather than dollars. How much does being overweight cut your life short? I’ll explore just that question, next.
Please consider volunteering to help out on the site.
- Sjöström L. Review of the key results from the Swedish Obese Subjects (SOS) trial-a prospective controlled intervention study of bariatric surgery. J Intern Med. 2013;273(3):219-34.
- Jahn J, Spielau M, Brandsch C, et al. Decreased NK cell functions in obesity can be reactivated by fat mass reduction. Obesity (Silver Spring). 2015;23(11):2233-41.
- Walsh NP, Gleeson M, Shephard RJ, et al. Position statement. Part one: immune function and exercise. Exerc Immunol Rev. 2011;17:6-63.
- Mokry LE, Ross S, Timpson NJ, Sawcer S, Davey Smith G, Richards JB. Obesity and multiple sclerosis: a Mendelian randomization study. PLoS Med. 2016;13(6):e1002053.
- Chen S, Akbar SM, Miyake T, et al. Diminished immune response to vaccinations in obesity: role of myeloid-derived suppressor and other myeloid cells. Obes Res Clin Pract. 2015;9(1):35-44.
- Gallacher J, McPherson S. Practical diagnosis and staging of nonalcoholic fatty liver disease: a narrative review. EMJ. 2018;3(2):108-18.
- Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of non-alcoholic fatty liver disease: practice guideline by the American Gastroenterological Association, American Association for the Study of Liver Diseases, and American College of Gastroenterology. Gastroenterology. 2012;142(7):1592-609.
- Calzadilla Bertot L, Adams LA. The natural course of non-alcoholic fatty liver disease. Int J Mol Sci. 2016;17(5):774.
- Noureddin M, Vipani A, Bresee C, et al. NASH leading cause of liver transplant in women: updated analysis of indications for liver transplant and ethnic and gender variances. Am J Gastroenterol. 2018;113(11):1649-59.
- Kovesdy CP, Furth SL, Zoccali C. Obesity and kidney disease: hidden consequences of the epidemic. Am J Nephrol. 2017;45:283-91.
- Forno E, Han YY, Mullen J, Celedón JC. Overweight, obesity, and lung function in children and adults-a meta-analysis. J Allergy Clin Immunol Pract. 2018;6(2):570-81.e10.
- Zafar U, Khaliq S, Ahmad HU, Manzoor S, Lone KP. Metabolic syndrome: an update on diagnostic criteria, pathogenesis, and genetic links. Hormones (Athens). 2018;17(3):299-313.
- Hogerzeil DP, Hartholt KA, de Vries MR. Xiphoidectomy: a surgical intervention for an underdocumented disorder. Case Rep Surg. 2016;2016:9306262.
- Kim DD, Basu A. Estimating the medical care costs of obesity in the United States: systematic review, meta-analysis, and empirical analysis. Value Health. 2016;19(5):602-13.
- McCrady-Spitzer SK, Levine JA. Nonexercise activity thermogenesis: a way forward to treat the worldwide obesity epidemic. Surg Obes Relat Dis. 2012;8(5):501-6.
- Bhattacharya J, Bundorf MK. The incidence of the healthcare costs of obesity. J Health Econ. 2009;28(3):649-58.
- Hamilton D, Dee A, Perry IJ. The lifetime costs of overweight and obesity in childhood and adolescence: a systematic review. Obes Rev. 2018;19(4):452-63.
- Wang YC, McPherson K, Marsh T, Gortmaker SL, Brown M. Health and economic burden of the projected obesity trends in the USA and the UK. Lancet. 2011;378(9793):815-25.
- van Baal PH, Polder JJ, de Wit GA, et al. Lifetime medical costs of obesity: prevention no cure for increasing health expenditure. PLoS Med. 2008;5(2):e29.
Video production by Glass Entertainment
Motion graphics by Avocado Video
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
In the ABCs of the health consequences of obesity, I is for Immunity.
The SOS trial, which followed the fates of thousands of bariatric surgery patients for a decade or two (compared to a control group that maintained their weight, and those who surgically lost about 20 percent of their body weight, not only lived longer, thanks in part to less diabetes and less cardiovascular disease, but they also got less cancer. This may be because anti-tumor immunity appears to be affected by weight. Natural killer cells are your immune system’s first line of defense against cancer cells (as well as many viral infections), and their function is severely impaired in obesity. Randomize obese individuals to a weight-loss program, though, and there was a significant reactivation of their natural killer cell function within just three months. The program involved an exercise component, though, and so it’s hard to tease out the impact of the weight loss itself, since physical activity alone can boost natural killer cell activity.
On the other end of the immune spectrum, obesity is suspected to be a causal risk factor for the development of the autoimmune disease multiple sclerosis. This suggests obesity is associated with the worst of both worlds when it comes to immune function: underactivity when it comes to protecting against cancer and infection, but overactivity when it comes to certain inflammatory autoimmune conditions.
J is for Jaundice. Thanks to the obesity epidemic, nonalcoholic fatty liver disease is now the most common liver disorder in the industrialized world. Fat doesn’t just end up in our belly and thighs, but inside some of our internal organs. More than 80 percent of individuals with abdominal obesity may have fatty infiltration into their liver, and in those with severe obesity, the prevalence can exceed 90 percent. This can lead to inflammation, scarring, and ultimately, cirrhosis and liver cancer. Currently, this nonalcoholic fatty hepatitis is the leading cause of liver transplants in American women, and men are expected to catch up in 2020.
K is for Kidneys. Obesity is also one of the strongest risk factors for chronic kidney diseases. Your kidneys compensate for the metabolic demands of the excess weight by red-lining into what’s called “hyperfiltration” to deal with the extra workload. This resulting increased pressure within the kidneys can damage the sensitive structures, and increase the risk of kidney failure over the long term.
What about L, M, N, O, P through Z? If you want to continue through the alphabet, the L could be for diminished lung function, M for metabolic syndrome, and so on…. There’s even an X—for xiphodynia—pain at the tip of the bottom of the breastbone from being bent forward by an expanding abdomen.
Given the myriad of health conditions associated with excess weight, annual medical spending attributable to obesity is nearly $2,000 per year, with obese workers with multiple conditions costing companies up to $10,000 more in healthcare coverage, compared to lean counterparts. This may actually account for some of the wage gap that obese employees experience, as companies try to pass along these costs beyond just brazen discrimination. Between healthcare costs and diminished productivity in terms of lost workdays, the total lifetime costs of obesity for children and teens has been estimated to exceed $150,000.
Some estimates peg the national cost of obesity at about $150 billion dollars, with another $50 billion per year added by 2030 as our increasingly heavy baby boomers continue to age. Others diametrically disagree, based on the morbid fact that obese individuals may not live as long. Just as the medical costs of tobacco-related diseases may be more than offset by the shortened survival of smokers, the lifetime healthcare costs of obese individuals may turn out to be lower because they are expected to die so much sooner. So, the true cost may be more in lives, rather than dollars. How much does being overweight cut your life short? I’ll explore just that question, next.
Please consider volunteering to help out on the site.
- Sjöström L. Review of the key results from the Swedish Obese Subjects (SOS) trial-a prospective controlled intervention study of bariatric surgery. J Intern Med. 2013;273(3):219-34.
- Jahn J, Spielau M, Brandsch C, et al. Decreased NK cell functions in obesity can be reactivated by fat mass reduction. Obesity (Silver Spring). 2015;23(11):2233-41.
- Walsh NP, Gleeson M, Shephard RJ, et al. Position statement. Part one: immune function and exercise. Exerc Immunol Rev. 2011;17:6-63.
- Mokry LE, Ross S, Timpson NJ, Sawcer S, Davey Smith G, Richards JB. Obesity and multiple sclerosis: a Mendelian randomization study. PLoS Med. 2016;13(6):e1002053.
- Chen S, Akbar SM, Miyake T, et al. Diminished immune response to vaccinations in obesity: role of myeloid-derived suppressor and other myeloid cells. Obes Res Clin Pract. 2015;9(1):35-44.
- Gallacher J, McPherson S. Practical diagnosis and staging of nonalcoholic fatty liver disease: a narrative review. EMJ. 2018;3(2):108-18.
- Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of non-alcoholic fatty liver disease: practice guideline by the American Gastroenterological Association, American Association for the Study of Liver Diseases, and American College of Gastroenterology. Gastroenterology. 2012;142(7):1592-609.
- Calzadilla Bertot L, Adams LA. The natural course of non-alcoholic fatty liver disease. Int J Mol Sci. 2016;17(5):774.
- Noureddin M, Vipani A, Bresee C, et al. NASH leading cause of liver transplant in women: updated analysis of indications for liver transplant and ethnic and gender variances. Am J Gastroenterol. 2018;113(11):1649-59.
- Kovesdy CP, Furth SL, Zoccali C. Obesity and kidney disease: hidden consequences of the epidemic. Am J Nephrol. 2017;45:283-91.
- Forno E, Han YY, Mullen J, Celedón JC. Overweight, obesity, and lung function in children and adults-a meta-analysis. J Allergy Clin Immunol Pract. 2018;6(2):570-81.e10.
- Zafar U, Khaliq S, Ahmad HU, Manzoor S, Lone KP. Metabolic syndrome: an update on diagnostic criteria, pathogenesis, and genetic links. Hormones (Athens). 2018;17(3):299-313.
- Hogerzeil DP, Hartholt KA, de Vries MR. Xiphoidectomy: a surgical intervention for an underdocumented disorder. Case Rep Surg. 2016;2016:9306262.
- Kim DD, Basu A. Estimating the medical care costs of obesity in the United States: systematic review, meta-analysis, and empirical analysis. Value Health. 2016;19(5):602-13.
- McCrady-Spitzer SK, Levine JA. Nonexercise activity thermogenesis: a way forward to treat the worldwide obesity epidemic. Surg Obes Relat Dis. 2012;8(5):501-6.
- Bhattacharya J, Bundorf MK. The incidence of the healthcare costs of obesity. J Health Econ. 2009;28(3):649-58.
- Hamilton D, Dee A, Perry IJ. The lifetime costs of overweight and obesity in childhood and adolescence: a systematic review. Obes Rev. 2018;19(4):452-63.
- Wang YC, McPherson K, Marsh T, Gortmaker SL, Brown M. Health and economic burden of the projected obesity trends in the USA and the UK. Lancet. 2011;378(9793):815-25.
- van Baal PH, Polder JJ, de Wit GA, et al. Lifetime medical costs of obesity: prevention no cure for increasing health expenditure. PLoS Med. 2008;5(2):e29.
Video production by Glass Entertainment
Motion graphics by Avocado Video
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The Effects of Obesity on the Immune System and Kidney and Liver Diseases
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Content URLDoctor's Note
If you missed the previous videos in my series on the ABCs of obesity, see:
- The Best Knee Replacement Alternative for Osteoarthritis Treatment
- The Effects of Obesity on Back Pain, Blood Pressure, Cancer, and Diabetes
- The Effects of Obesity on Dementia, Brain Function, and Fertility
- The Effects of Obesity on Gallstones, Acid Reflux, and Cardiovascular Disease
I continue the topic of obesity and weight with these videos:
For more on the health conditions discussed in this video, see the immune function, kidney disease, and liver health topic pages.
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