Scientists have proposed that inflammation is the forerunner of aging and central to the aging process, a phenomenon that has been described as “inflamm-aging”.
Lin, L., et al (2016) looked at the association between certain hormones and aging, low grade adipose (fat) inflammation, insulin resistance and type 2 diabetes.
The Ghrelin Connection
Ghrelin is a hormone that enhances appetite (orexigenic). It has been shown to increase weight gain, promote obesity and lead to insulin resistance.
The pharmaceutical industry has been calling ghrelin “the key to obesity”.
Aside from its role in appetite, ghrelin signals adipose tissue to produce macrophages, a type of white blood cell that is central to inflammation and immunity.
WAT and BAT
Obesity is regarded as low-grade, chronic inflammation in adipose tissues. Adipose tissue (specifically visceral or “belly fat”) serves as a major endocrine organ, secreting various hormones and cytokines (inflammatory cell signaling molecules), which play crucial roles in normal metabolism and obesity-associated dysfunctions.
There are 2 types of adipose tissues:
- WAT (White Adipose Tissue) and
- BAT (Brown Adipose Tissue)
The function of white adipose tissue is to store excess lipids in the body and supply free fatty acids as energy as needed. Excess WAT increases inflammation and is closely linked to insulin resistance.
The function of BAT is to break down lipids to generate heat, which in turn burns fat.
The current literature suggests that macrophages play central roles in inflammation/immune responses as well as the stress response. They are also a major mediator of inflammation in the body, and have been shown to positively correlate with age-associated metabolic complications, neurodegenerative diseases (Alzheimer’s and Parkinson’s) and cardiovascular diseases.
There are two subsets of macrophage-like substances:
- Pro-inflammatory M1
- Anti-inflammatory M2
M1-like macrophages are associated with an obese and insulin-resistant state, while M2-like macrophages are associated with a lean and insulin-sensitive state.
M2-like macrophages also release the “fight or flight” response hormone norepinephrine, promoting lipid mobilization in white adipose tissue and thermogenesis, or heat production, in brown adipose tissue.
Lin, L., Lee, J. H., Buras, E. D., Yu, K., Wang, R., Smith, C. W., … & Sun, Y. (2016). Ghrelin receptor regulates adipose tissue inflammation in aging.Aging (Albany NY), 8(1), 178.
Inflamm-Aging in not an inevitable consequence of aging, but a modifiable process that can be manipulated through optimizing one’s diet and lifestyle.
Avoid MSG and Aspartame
Aspartame and Monosodium Glutamate (MSG) are common food additives containing acidic amino acids which can act as neurotransmitters, interacting with receptors in the central nervous system regulating energy expenditure and conservation.
MSG has been shown to promote a neuroendocrine dysfunction, reduce leptin levels and increase appetite.
Aspartame is a low-calorie dipeptide sweetener found in a wide variety of diet beverages and foods which may promote weight gain and hyperglycemia.
Collison, K. S., Makhoul, N. J., Zaidi, M. Z., Al-Rabiah, R., Inglis, A., Andres, B. L., … & Al-Mohanna, F. A. (2012). Interactive effects of neonatal exposure to monosodium glutamate and aspartame on glucose homeostasis. Nutrition & metabolism, 9(1), 1.
Fernandez-Tresguerres, H. J. (2004, December). [Effect of monosodium glutamate given orally on appetite control (a new theory for the obesity epidemic)]. In Anales de la Real Academia Nacional de Medicina (Vol. 122, No. 2, pp. 341-55).
de Matos Feijó, F., Ballard, C. R., Foletto, K. C., Batista, B. A. M., Neves, A. M., Ribeiro, M. F. M., & Bertoluci, M. C. (2013). Saccharin and aspartame, compared with sucrose, induce greater weight gain in adult Wistar rats, at similar total caloric intake levels. Appetite, 60, 203-207.
Avoid High Fructose Corn Syrup
Insulin, leptin and ghrelin function as key signals to the central nervous system in the long-term regulation of energy balance.
With chronic consumption of high fructose corn syrup, decreased circulating insulin and leptin and increased ghrelin concentrations can lead to increased caloric intake and ultimately contribute to weight gain and obesity.
Teff, K. L., Elliott, S. S., Tschöp, M., Kieffer, T. J., Rader, D., Heiman, M., … & Havel, P. J. (2004). Dietary fructose reduces circulating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. The Journal of Clinical Endocrinology & Metabolism, 89(6), 2963-2972.
Decrease Your Salt Intake
Ghrelin, which regulates appetite, food intake, and fat deposition, becomes elevated when one consumes a high-salt diet, contributing to the progression of obesity.
Zhang, Y., Li, F., Liu, F. Q., Chu, C., Wang, Y., Wang, D., … & Mu, J. J. (2016). Elevation of Fasting Ghrelin in Healthy Human Subjects Consuming a High-Salt Diet: A Novel Mechanism of Obesity?. Nutrients, 8(6), 323.
Increase Your Fiber Intake
Fiber intake reduces ghrelin and has been linked to the prevention of a range of illnesses and conditions, such as metabolic syndrome, obesity, improved glucose levels and blood lipids, as well as the control of blood pressure.
Aleixandre, A., & Miguel, M. (2008). Dietary fiber in the prevention and treatment of metabolic syndrome: a review. Critical reviews in food science and nutrition, 48(10), 905-912.
St-Pierre, D. H., Rabasa-Lhoret, R., Lavoie, M. È., Karelis, A. D., Strychar, I., Doucet, E., & Coderre, L. (2009). Fiber intake predicts ghrelin levels in overweight and obese postmenopausal women. European Journal of Endocrinology, 161(1), 65-72.
Increase Your Protein
A high-protein diet is more satiating than a high-carbohydrate diet through suppression of postprandial ghrelin concentrations.
Blom, W. A., Lluch, A., Stafleu, A., Vinoy, S., Holst, J. J., Schaafsma, G., & Hendriks, H. F. (2006). Effect of a high-protein breakfast on the postprandial ghrelin response. The American journal of clinical nutrition, 83(2), 211-220.
Leidy, H. J., Armstrong, C. L., Tang, M., Mattes, R. D., & Campbell, W. W. (2010). The influence of higher protein intake and greater eating frequency on appetite control in overweight and obese men. Obesity, 18(9), 1725-1732.
Increase Omega-3 Fats
The quality and quantity of fat in the diet play important roles in glucose homeostasis and insulin sensitivity.
Ghrelin is important in the regulation of insulin secretion, insulin sensitivity, and glucose metabolism.
Diets containing monounsaturated fatty acids and omega 3 polyunsaturated fats result in lower food and calorie intake and lower weight gain.
These changes were associated with fasting ghrelin concentrations, concomitant with lower insulin concentration and insulin resistance.
Saidpour, A., Zahediasl, S., Kimiagar, M., Vafa, M., Ghasemi, A., Abadi, A., … Zarkesh, M. (2011). Fish oil and olive oil can modify insulin resistance and plasma desacyl-ghrelin in rats. Journal of Research in Medical Sciences : The Official Journal of Isfahan University of Medical Sciences, 16(7), 862–871.
Probiotics/Prebiotics and the Gut Microbiome
The scientific literature documents several favorable effects of prebiotics, probiotics and a healthy gut microbiome on food intake, body weight, glucose homeostasis, plasma lipid profile, and associated risk factors for cardiovascular disease.
Several mechanisms have been proposed, such as the effects of ghrelin on appetite.
Mallappa, R. H., Rokana, N., Duary, R. K., Panwar, H., Batish, V. K., & Grover, S. (2012). Management of metabolic syndrome through probiotic and prebiotic interventions. Indian Journal of Endocrinology and Metabolism, 16(1), 20–27. http://doi.org/10.4103/2230-8210.91178
Chronic sleep loss is endemic in modern society.
Sleep exerts marked modulatory effects on glucose metabolism, as well as increasing the risk for diabetes and obesity when deficient.
The neuroendocrine regulation of appetite is also affected by poor sleep hygiene. The levels of the anorexigenic (appetite suppressant) hormone leptin are decreased, whereas the levels of the orexigenic (appetite stimulating) hormone ghrelin are increased with poor sleep.
Ultimately these neuroendocrine abnormalities are correlated with increased hunger and appetite, leading to overeating and weight gain.
Spiegel, K., Knutson, K., Leproult, R., Tasali, E., & Van Cauter, E. (2005). Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes.Journal of applied physiology, 99(5), 2008-2019.
Chronic or severe stress results in elevated glucocorticoid secretion, which increases circulating ghrelin levels and associated food intake.
Nishizawa, T., Suzuki, H., Masaoka, T., Nomoto, Y., Minegishi, Y., Hosoda, H., … & Hibi, T. (2006). Emotional stress enhanced ghrelin secretion from the stomach. Journal of Clinical Biochemistry and Nutrition, 38(1), 33-37.
Sominsky, L., & Spencer, S. J. (2014). Eating behavior and stress: a pathway to obesity. Frontiers in Psychology, 5, 434. http://doi.org/10.3389/fpsyg.2014.00434
Practical Applications to Reduce Inflamm-Aging
- Avoid Aspartame http://www.md-health.com/What-Foods-Contain-Aspartame.html
- Avoid High Fructose Corn Syrup http://www.celestialhealing.net/Food_contain_HFCS.htm
- Decrease Salt (< 1,500 milligrams of sodium per day)
- Increase fiber http://www.webmd.com/diet/guide/fiber-how-much-do-you-need#1
- Include protein with every meal
- Eat more cold water fish for omega 3 fats
- Increase intake of cultured foods http://drgeofflecovin.com/?p=906
- Aim for 7-9 hours of sleep per night
- Manage your stress, e.g. meditate for 15 minutes daily in a quiet space