UNIT 3 - PLANT-BASED DIET AND AUTOIMMUNE DISEASES |
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Plant-based diet and Autoimmune disease
Rheumatoid arthritis Multiple sclerosis Systemic Lupus Erythematosus Irritable bowel syndrome Article review Video review |
OBJECTIVES:
- Describe the importance of plant-based diet in autoimmune diseases.
- Discuss the probability of remission in through plant-based diet.
- Understand the nutritional considerations for common autoimmune disorders.
- Neal Barnard, MD, (2009). Nutrition Guide for Clinicians.
- Michael Greger, MD, (2011). Nutrition Facts.
- Myositis Association, (2019). Nutrition for Autoimmune Diseases.
- Northwest Vege (2013). Multiple Sclerosis and Autoimmune Diseases: The Impact of Diet - John McDougall, MD
Plant-based Diet and Autoimmune Disease
Dietary triggers may play an inciting role in the autoimmune process, and a compromised intestinal barrier may allow food components or microorganisms to enter the blood stream, triggering inflammation. In addition, excessive body weight may affect pharmacotherapy response and the likelihood of disease remission, as well as the risk of disease mortality.
Several studies have reported lower risk of autoimmune diseases with a vegan diet. A 2013 study, using data from the Adventist Health Study-2 (AHS-2) cohort (n = 65,981), described a lower incidence and prevalence of hypothyroidism in people following vegan diets, compared to omnivorous, lacto-ovovegetarian, semi-vegetarian, and pesco-vegetarian diets even after controlling for BMI and demographic variables. The researchers speculated that the inflammatory properties of animal products could explain the lower risk in vegans.
These results suggest that a vegan diet, with a high intake of fruits and vegetables and the elimination of animal products, could protect against the development of autoimmune conditions. In contrast, diets high in animal products and low in fiber might increase the risk of developing these autoimmune conditions.
Intestinal gut health might play a role in the observed anti-inflammatory effects of dietary fiber. Studies have shown that dietary fiber can alter the composition of gut bacteria and increase the bacterial diversity, which is oftentimes lacking in RA patients, thus preventing intestinal damage.
Accumulating scientific evidence supports the health advantages of vegetarian diets. Vegetarian diets are characterized by reduced or eliminated consumption of animal products but may include dairy products and/or eggs, while vegan diets contain only plant foods.
A high-protein diet (28% protein, 43% carbohydrate, 13 g fiber) reduced insulin sensitivity by 12% while a high cereal fiber diet (17% protein, 52% carbohydrate, 43 g fiber) improved insulin sensitivity by 13% in 111 overweight and obese participants. Participants assigned to the high fiber diet displayed 25% higher insulin sensitivity than those on the high protein diet after the 6-week intervention. These results indicate that high dietary protein (≥25–30% of energy) induces insulin resistance. Interestingly, insulin sensitivity was not significantly altered after 6 weeks of a mixed diet (23% protein, 44% carbohydrate, 26 g fiber). While dietary proteins are normally degraded by enzymes in the upper gut, these results indicate that cereal fibers may impede protein absorption in the small intestine. Thus, a low-glycemic, high-fiber and low-protein diet could mediate inflammation by decreasing pro-inflammatory gene expression and improving insulin sensitivity, even after significant reductions in inflammatory markers due to weight loss. Cross-sectional data from the Nurses' Health Study was analyzed and the association between total, unprocessed, and processed meat intake with CRP and adiponectin were measured. Greater total, unprocessed, and processed red meat intakes were associated with significantly higher plasma CRP concentrations and lower adiponectin levels for participants in the highest quintiles of these groups. Similarly, lower CRP values were associated with substituting a serving of total red meat with a combination of alternative protein sources (including poultry, fish, legumes, or nuts).
Several studies have reported lower risk of autoimmune diseases with a vegan diet. A 2013 study, using data from the Adventist Health Study-2 (AHS-2) cohort (n = 65,981), described a lower incidence and prevalence of hypothyroidism in people following vegan diets, compared to omnivorous, lacto-ovovegetarian, semi-vegetarian, and pesco-vegetarian diets even after controlling for BMI and demographic variables. The researchers speculated that the inflammatory properties of animal products could explain the lower risk in vegans.
These results suggest that a vegan diet, with a high intake of fruits and vegetables and the elimination of animal products, could protect against the development of autoimmune conditions. In contrast, diets high in animal products and low in fiber might increase the risk of developing these autoimmune conditions.
Intestinal gut health might play a role in the observed anti-inflammatory effects of dietary fiber. Studies have shown that dietary fiber can alter the composition of gut bacteria and increase the bacterial diversity, which is oftentimes lacking in RA patients, thus preventing intestinal damage.
Accumulating scientific evidence supports the health advantages of vegetarian diets. Vegetarian diets are characterized by reduced or eliminated consumption of animal products but may include dairy products and/or eggs, while vegan diets contain only plant foods.
A high-protein diet (28% protein, 43% carbohydrate, 13 g fiber) reduced insulin sensitivity by 12% while a high cereal fiber diet (17% protein, 52% carbohydrate, 43 g fiber) improved insulin sensitivity by 13% in 111 overweight and obese participants. Participants assigned to the high fiber diet displayed 25% higher insulin sensitivity than those on the high protein diet after the 6-week intervention. These results indicate that high dietary protein (≥25–30% of energy) induces insulin resistance. Interestingly, insulin sensitivity was not significantly altered after 6 weeks of a mixed diet (23% protein, 44% carbohydrate, 26 g fiber). While dietary proteins are normally degraded by enzymes in the upper gut, these results indicate that cereal fibers may impede protein absorption in the small intestine. Thus, a low-glycemic, high-fiber and low-protein diet could mediate inflammation by decreasing pro-inflammatory gene expression and improving insulin sensitivity, even after significant reductions in inflammatory markers due to weight loss. Cross-sectional data from the Nurses' Health Study was analyzed and the association between total, unprocessed, and processed meat intake with CRP and adiponectin were measured. Greater total, unprocessed, and processed red meat intakes were associated with significantly higher plasma CRP concentrations and lower adiponectin levels for participants in the highest quintiles of these groups. Similarly, lower CRP values were associated with substituting a serving of total red meat with a combination of alternative protein sources (including poultry, fish, legumes, or nuts).
RHEUMATOID ARTHRITIS
Rheumatoid arthritis (RA), a chronic inflammatory autoimmune disease, affects roughly 1% of the world's population. RA pathogenesis remains unclear, but genetic factors account for 50–60% of the risk while the remainder might be linked to modifiable factors, such as infectious diseases, tobacco smoking, gut bacteria, and nutrition.
Rheumatoid arthritis (RA), a chronic inflammatory autoimmune disease, affects roughly 1% of the world's population. RA pathogenesis remains unclear, but genetic factors account for 50–60% of the risk while the remainder might be linked to modifiable factors, such as infectious diseases, tobacco smoking, gut bacteria, and nutrition.
Rheumatoid arthritis (RA), a chronic inflammatory autoimmune disease, affects roughly 1% of the world's population. Hands, wrists, and knees are most commonly bilaterally affected causing inflammation, pain, and eventually permanent joint damage. Genetic factors may account for a portion of risk, while the rest might be linked to environmental factors or a combination of genetic and environmental factors. Infectious diseases, tobacco smoking, and gut bacteria have all been considered to play a role in the development or progression of RA. Medications are a mainstay of treatment, but have unwanted side effects or are often expensive. Thus, changes in diet might be an easy and economical intervention in the management of RA.
Several studies have shown a correlation between modifiable risk factors and improvement of symptoms and outcomes in RA patients. Excessive body weight and diets that include animal products (e.g., dairy and red meat) tend to impair RA management efforts and exacerbate symptoms, presumably due to their pro-inflammatory effects. In contrast, diets rich in vegetables, fruits, and fiber are associated with lower BMI, have anti-inflammatory properties and help reduce pain and inflammation in these patients. Specifically, a 4-weeks low-fat vegan diet has been shown to significantly improve RA symptoms such as joint pain, stiffness, swelling and limitation in function. Likewise, a 1-year intervention tested the effects of a 7–10 day fast, followed by 3.5 months of a gluten-free vegan diet and gradual adoption of a vegetarian diet for the remainder of the study period. Significant improvements in several RA disease activity variables were observed after 1 month, including: number of tender joints, Ritchie's articular index, number of swollen joints, pain score, duration of morning stiffness, grip strength, erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and a health assessment questionnaire score. These improvements were maintained after 1 year.
A 2015 study (n = 50) observed reductions in inflammatory scores in overweight or obese, otherwise healthy, participants randomized to a 2-month vegan, vegetarian, or pesco-vegetarian dietary intervention (p < 0.05) compared to those placed on a semi-vegetarian or omnivorous diet. Subjects in all five groups were counseled to choose low-fat foods, but only the vegan participants met the mean percentage energy from fat and saturated fat (≤30% energy from fat and ≤7% energy from saturated fat) recommendations. The researchers attributed this observation to the elimination of the leading sources of fat in the western diet (beef, cheese, milk, and poultry; 8). Diets high in fat and processed meat have been positive associated with inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), and homocysteine, while diets high in whole grains and fruit have been inversely associated with these biomarkers. Likewise, vegetarian diets are negatively associated with CRP levels (p < 0.000). Furthermore, a 3-week vegan lifestyle intervention resulted in a 33% reduction in CRP levels (p < 0.001), which was attributed to the anti-inflammatory components of the vegan diet, such as high fiber intake (>49 g/day).
Research has found that a low-fat vegan diet improves RA symptoms, such as the degree of pain, joint tenderness, and joint swelling. A randomized clinical trial found that a gluten-free vegan diet decreases immunoglobulin G (IgG) in RA patients, an oftentimes elevated pro-inflammatory antibody. A Cretan Mediterranean Diet, rich in olive oil, cereals, vegetables, fruits, and legumes, also resulted in significant improvements in Disease Activity Score (DAS28), Health Assessment Questionnaire (HAQ), C-Reactive Protein (CRP), and swollen joint counts in patients with RA. However, further investigation is needed as previous research has also shown that a high-fat diet may change the composition of the gut bacteria and be linked to inflammation.
The naturally low-fat, fiber-rich components of a vegan diet might mediate the pathways that alleviate joint inflammation and pain, as observed through reduced CRP levels and improved inflammatory scores. These findings highlight the need for a randomized study that objectively measures biomarkers of inflammation related to plant-based dietary changes.
Higher red meat intake has been positively associated with inflammatory polyarthritis (p = 0.04). Participants consuming the highest levels of red meat (OR 1.9, 95% CI 0.9–4.0), total meat (OR 2.3, 95% CI 1.1–4.9), and total protein (OR 2.9, 95% CI 1.1–7.5), displayed a higher risk for inflammatory polyarthritis when compared to participants with lower meat and protein intakes (58). These findings suggest that meat intake increases the risk of inflammatory arthritis.
Several studies have shown a correlation between modifiable risk factors and improvement of symptoms and outcomes in RA patients. Excessive body weight and diets that include animal products (e.g., dairy and red meat) tend to impair RA management efforts and exacerbate symptoms, presumably due to their pro-inflammatory effects. In contrast, diets rich in vegetables, fruits, and fiber are associated with lower BMI, have anti-inflammatory properties and help reduce pain and inflammation in these patients. Specifically, a 4-weeks low-fat vegan diet has been shown to significantly improve RA symptoms such as joint pain, stiffness, swelling and limitation in function. Likewise, a 1-year intervention tested the effects of a 7–10 day fast, followed by 3.5 months of a gluten-free vegan diet and gradual adoption of a vegetarian diet for the remainder of the study period. Significant improvements in several RA disease activity variables were observed after 1 month, including: number of tender joints, Ritchie's articular index, number of swollen joints, pain score, duration of morning stiffness, grip strength, erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and a health assessment questionnaire score. These improvements were maintained after 1 year.
A 2015 study (n = 50) observed reductions in inflammatory scores in overweight or obese, otherwise healthy, participants randomized to a 2-month vegan, vegetarian, or pesco-vegetarian dietary intervention (p < 0.05) compared to those placed on a semi-vegetarian or omnivorous diet. Subjects in all five groups were counseled to choose low-fat foods, but only the vegan participants met the mean percentage energy from fat and saturated fat (≤30% energy from fat and ≤7% energy from saturated fat) recommendations. The researchers attributed this observation to the elimination of the leading sources of fat in the western diet (beef, cheese, milk, and poultry; 8). Diets high in fat and processed meat have been positive associated with inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), and homocysteine, while diets high in whole grains and fruit have been inversely associated with these biomarkers. Likewise, vegetarian diets are negatively associated with CRP levels (p < 0.000). Furthermore, a 3-week vegan lifestyle intervention resulted in a 33% reduction in CRP levels (p < 0.001), which was attributed to the anti-inflammatory components of the vegan diet, such as high fiber intake (>49 g/day).
Research has found that a low-fat vegan diet improves RA symptoms, such as the degree of pain, joint tenderness, and joint swelling. A randomized clinical trial found that a gluten-free vegan diet decreases immunoglobulin G (IgG) in RA patients, an oftentimes elevated pro-inflammatory antibody. A Cretan Mediterranean Diet, rich in olive oil, cereals, vegetables, fruits, and legumes, also resulted in significant improvements in Disease Activity Score (DAS28), Health Assessment Questionnaire (HAQ), C-Reactive Protein (CRP), and swollen joint counts in patients with RA. However, further investigation is needed as previous research has also shown that a high-fat diet may change the composition of the gut bacteria and be linked to inflammation.
The naturally low-fat, fiber-rich components of a vegan diet might mediate the pathways that alleviate joint inflammation and pain, as observed through reduced CRP levels and improved inflammatory scores. These findings highlight the need for a randomized study that objectively measures biomarkers of inflammation related to plant-based dietary changes.
Higher red meat intake has been positively associated with inflammatory polyarthritis (p = 0.04). Participants consuming the highest levels of red meat (OR 1.9, 95% CI 0.9–4.0), total meat (OR 2.3, 95% CI 1.1–4.9), and total protein (OR 2.9, 95% CI 1.1–7.5), displayed a higher risk for inflammatory polyarthritis when compared to participants with lower meat and protein intakes (58). These findings suggest that meat intake increases the risk of inflammatory arthritis.
MULTIPLE SCLEROSIS
Lauer et al. examined risk factors for multiple sclerosis, an autoimmune disease of the central nervous system, in male World War II veterans using the 1993 nationwide case-control study (n = 10,610). In the U.S, meat and dairy sales were significantly correlated with multiple sclerosis risk, while inverse associations were found with fruit and vegetable sales. Affluence was also positively associated with multiple sclerosis risk, corresponding with increased meat and dairy consumption with higher socioeconomic status.
The role of diet in ameliorating the severity of multiple sclerosis (MS) has been long debated, but there remains a paucity of relevant research. Observational studies by Dr. Roy Swank, published between 1953 and 2003, suggested significantly reduced MS disease activity and disability progression and longer survival in people following a diet low in total and saturated fat compared with those who did not (Swank, 1953; Swank and Goodwin, 2003; Swank, 1970). Swank's diet book, last published in 1987, remains popular among patients with MS. However, this approach to treating MS has never been subjected to a well-controlled clinical trial. The supposed large clinical effect of the Swank low fat diet led to our hypothesis that a very-low-fat, plant-based diet might have a large effect on MRI activity. We conducted a pilot study to explore the tolerability and potential benefits of a very-low saturated fat, plant-based diet followed for 12 months by people with relapsing-remitting MS (RRMS) with the primary endpoint being brain MRI disease activity.
SYSTEMATIC LUPUS ERYTHEMATOSUS
Research on dietary influences on SLE has focused on vitamin D, vitamin A and polyunsaturated fatty acids. Dietary changes in SLE, meaning diet supplementation with vitamins A, D, E, polyunsaturated fatty acids and phytoestrogens showed a decrease in proteinuria and glomerulonephritis in animal models.
There is now clear evidence that environmental factors have a high influence on SLE development, since there is a lower prevalence of the disease in West Africans than in African Americans, though both groups have the same ethnicity. The proposed theories to support this difference include the use of antibiotics and the hygiene hypothesis, which lead to the removal of some species of microbes that may have a protective role against SLE.
The outstanding role that food plays is sustained not only by its nutritional value, but also by its capacity to modify the structure and function of the gut microbiota.
An adequate diet is also important to help fight the associated comorbidities in SLE which increase the cardiovascular risk: diabetes mellitus, metabolic syndrome, dyslipidemia and obesity. The lipid profile alterations due to medication (chronic corticotherapy) or as a result of disease activity, are aggravated by hyperlipid diet. Higher levels of total cholesterol and very-low-density lipoprotein cholesterol (VLDL-C), an increase in triglycerides (TG) and a decrease in high-density lipoprotein cholesterol (HDL-C) have been noted.
Lauer et al. examined risk factors for multiple sclerosis, an autoimmune disease of the central nervous system, in male World War II veterans using the 1993 nationwide case-control study (n = 10,610). In the U.S, meat and dairy sales were significantly correlated with multiple sclerosis risk, while inverse associations were found with fruit and vegetable sales. Affluence was also positively associated with multiple sclerosis risk, corresponding with increased meat and dairy consumption with higher socioeconomic status.
The role of diet in ameliorating the severity of multiple sclerosis (MS) has been long debated, but there remains a paucity of relevant research. Observational studies by Dr. Roy Swank, published between 1953 and 2003, suggested significantly reduced MS disease activity and disability progression and longer survival in people following a diet low in total and saturated fat compared with those who did not (Swank, 1953; Swank and Goodwin, 2003; Swank, 1970). Swank's diet book, last published in 1987, remains popular among patients with MS. However, this approach to treating MS has never been subjected to a well-controlled clinical trial. The supposed large clinical effect of the Swank low fat diet led to our hypothesis that a very-low-fat, plant-based diet might have a large effect on MRI activity. We conducted a pilot study to explore the tolerability and potential benefits of a very-low saturated fat, plant-based diet followed for 12 months by people with relapsing-remitting MS (RRMS) with the primary endpoint being brain MRI disease activity.
SYSTEMATIC LUPUS ERYTHEMATOSUS
Research on dietary influences on SLE has focused on vitamin D, vitamin A and polyunsaturated fatty acids. Dietary changes in SLE, meaning diet supplementation with vitamins A, D, E, polyunsaturated fatty acids and phytoestrogens showed a decrease in proteinuria and glomerulonephritis in animal models.
There is now clear evidence that environmental factors have a high influence on SLE development, since there is a lower prevalence of the disease in West Africans than in African Americans, though both groups have the same ethnicity. The proposed theories to support this difference include the use of antibiotics and the hygiene hypothesis, which lead to the removal of some species of microbes that may have a protective role against SLE.
The outstanding role that food plays is sustained not only by its nutritional value, but also by its capacity to modify the structure and function of the gut microbiota.
An adequate diet is also important to help fight the associated comorbidities in SLE which increase the cardiovascular risk: diabetes mellitus, metabolic syndrome, dyslipidemia and obesity. The lipid profile alterations due to medication (chronic corticotherapy) or as a result of disease activity, are aggravated by hyperlipid diet. Higher levels of total cholesterol and very-low-density lipoprotein cholesterol (VLDL-C), an increase in triglycerides (TG) and a decrease in high-density lipoprotein cholesterol (HDL-C) have been noted.
IRRITABLE BOWEL SYNDROME
With a prevalence of approximately 10% worldwide, irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders. Patients with IBS do not have readily identifiable underlying structural abnormalities, but the diagnosis is made based on the current diagnostic standard, the Rome IV criteria, as: Recurrent abdominal pain, on average, at least 1 day/week, associated with 2 or more of the following criteria: related to defecation; associated with a change in frequency of stool; and associated with a change in form (appearance) of stool. The criteria should be fulfilled for the last 3 months with a symptom onset at least 6 months before the diagnosis. Based on the dominant stool form or consistency, IBS is also subtyped into IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed IBS (IBS-M), and unspecified IBS (IBS-U). The syndrome is one of the leading causes for consultations in gastroenterology outpatient clinics, as well as in primary care, and the most common reason for referral to gastroenterology clinics. Symptoms interfere with the daily life of many patients, reduce health-related quality of life and lower the work productivity.
IBS is currently described as a disorder of disturbed gut–brain interactions, with a heterogeneous and incompletely understood pathophysiology. Altered gut-brain interactions, visceral hypersensitivity, psychosocial distress, and gastrointestinal motor disturbances are considered to be of importance for IBS or at least subsets of patients. Moreover, over the past years, the number of factors that contribute to the pathophysiology has expanded. Intestinal immune activation, increased intestinal permeability, an altered microbiome, and food hypersensitivity are examples of other factors that can contribute to symptoms in subsets of IBS patients.
Dietary fibers are non-digestible carbohydrates (e.g., cellulose, resistant starch and glucans), which form key structural materials of cereals, fruits, vegetables and legumes. Fibers can be divided into two main groups, based on water solubility: soluble and insoluble fibers. In the GI tract, soluble fibers form a gel that interacts with gut bacteria and can shorten GI transit. The bacteria produce active metabolites such as short chain fatty acids, which interact with inflammatory pathways. Thus, short chain fatty acids link the gut microbiome with the metabolic profile of the host. In contrary, insoluble fibers barely change in the GI tract. Besides water solubility, several other chemical and physical characteristics of fiber foods influence the gut physiology, such as fermentability, viscosity and bulking/binding capacity. Previous studies have demonstrated that high intake of insoluble fibers increases water content and fecal bulking, resulting in accelerated GI transit time. This is a likely explanation of the benefit of high dietary fiber intake in IBS patients with predominant constipation (IBS-C). However, the largest problem with fiber intake is the formation of gas, which may lead to bloating, abdominal distension and flatulence, but this problem seems to be less prominent with soluble than with insoluble fibers
With a prevalence of approximately 10% worldwide, irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders. Patients with IBS do not have readily identifiable underlying structural abnormalities, but the diagnosis is made based on the current diagnostic standard, the Rome IV criteria, as: Recurrent abdominal pain, on average, at least 1 day/week, associated with 2 or more of the following criteria: related to defecation; associated with a change in frequency of stool; and associated with a change in form (appearance) of stool. The criteria should be fulfilled for the last 3 months with a symptom onset at least 6 months before the diagnosis. Based on the dominant stool form or consistency, IBS is also subtyped into IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed IBS (IBS-M), and unspecified IBS (IBS-U). The syndrome is one of the leading causes for consultations in gastroenterology outpatient clinics, as well as in primary care, and the most common reason for referral to gastroenterology clinics. Symptoms interfere with the daily life of many patients, reduce health-related quality of life and lower the work productivity.
IBS is currently described as a disorder of disturbed gut–brain interactions, with a heterogeneous and incompletely understood pathophysiology. Altered gut-brain interactions, visceral hypersensitivity, psychosocial distress, and gastrointestinal motor disturbances are considered to be of importance for IBS or at least subsets of patients. Moreover, over the past years, the number of factors that contribute to the pathophysiology has expanded. Intestinal immune activation, increased intestinal permeability, an altered microbiome, and food hypersensitivity are examples of other factors that can contribute to symptoms in subsets of IBS patients.
Dietary fibers are non-digestible carbohydrates (e.g., cellulose, resistant starch and glucans), which form key structural materials of cereals, fruits, vegetables and legumes. Fibers can be divided into two main groups, based on water solubility: soluble and insoluble fibers. In the GI tract, soluble fibers form a gel that interacts with gut bacteria and can shorten GI transit. The bacteria produce active metabolites such as short chain fatty acids, which interact with inflammatory pathways. Thus, short chain fatty acids link the gut microbiome with the metabolic profile of the host. In contrary, insoluble fibers barely change in the GI tract. Besides water solubility, several other chemical and physical characteristics of fiber foods influence the gut physiology, such as fermentability, viscosity and bulking/binding capacity. Previous studies have demonstrated that high intake of insoluble fibers increases water content and fecal bulking, resulting in accelerated GI transit time. This is a likely explanation of the benefit of high dietary fiber intake in IBS patients with predominant constipation (IBS-C). However, the largest problem with fiber intake is the formation of gas, which may lead to bloating, abdominal distension and flatulence, but this problem seems to be less prominent with soluble than with insoluble fibers
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Unit Task
Submit your Reflective Journal after watching the videos, reading the lesson and article.