Best of Dietary Fiber and Heart DiseaseDecember 30, 2010 Written by JP [Font too small?]
Some people like to play board games, watch sporting events or knit in their spare time. Me? I like to browse around the Centers for Disease Control and Prevention web site. I sometimes search around there for statistics that help shape the content that ends up here. The other day I found a few interesting facts and figures. I already knew that heart disease is the “leading cause of death for both women and men in the United States”. But I was still stunned by a few other statistics. In 2005, 7.6 million people’s lives ended prematurely due to coronary heart disease. In 2003, almost 40% of adults exhibited two or more of six risk factors for heart disease and stroke (diabetes, high blood pressure, high cholesterol, obesity, physical inactivity and smoking). These figures have probably only gotten worse in the time since they were compiled. This is evidenced by the most recent figure available: “In 2009, heart disease is projected to cost more than $304 billion dollars, including health care services, medications and lost productivity.”
Several months ago I wrote a column highlighting recent evidence that a high fiber diet can help protect against a variety of cancers. Today I’ll focus on the role that this dietary component can play in helping to reduce the risk of developing cardiovascular disease and all of its related complications.
In July 2010, a study appeared in the Journal of Epidemiological Community Health. 772 volunteers who were at high risk for cardiovascular disease participated in this trial. They were all assigned either a low fat diet or one of two “Mediterranean style diets” for a 3 month period. Dietary questionnaires were administered to determine nutrient intake and blood tests were taken pre and post trial.
- The volunteers who consumed the most fiber (the upper 20%) showed the greatest declines in fasting blood sugar and total cholesterol. They also demonstrated higher HDL “good” cholesterol readings.
- LDL “bad” cholesterol only dropped significantly in those who ate the largest quantities of soluble fiber, which is found in such as foods as berries, broccoli, chia and psyllium seed supplements.
- Reductions in C-reactive protein, an inflammatory marker, were also found in those consuming the largest amount of fiber.
The authors of the trial concluded that, “increasing dietary fiber intake with natural foods is associated with reductions in classical and novel cardiovascular risk factors in a high-risk cohort”. (1)
Another recent study presented in the European Journal of Clinical Nutrition determined that eating foods rich in any kind of fiber (insoluble, soluble or total fiber) may result in a reduced likelihood of stroke by up to 36%. These findings are based on a population study of over 26,000 Finnish male smokers with ages ranging from 50 – 69. This is, again, considered a high-risk group that apparently was afforded potentially life saving support via adequate to optimal fiber consumption. (2)
If dietary fiber does, in fact, protect from cardiovascular disease, then there must be a mechanism behind its ability to do so. Here are some of the proposed ways that roughage may shield against heart disease and strokes.
- Blood Pressure – Both population and scientifically controlled studies frequently find that higher levels of dietary fiber are associated with lower blood pressure (BP) readings – a risk factor for both heart disease and stroke. A current study also discovered that replacing a low fiber, refined bread with a higher fiber bread resulted in decreased systolic BP and pulse pressure. (3,4,5)
- Chronic Inflammation – A recent scientific review of the medical literature examined 7 studies that related to fiber consumption and levels of the inflammatory marker, C-reactive protein (CRP). CRP may contribute to hardening of the arteries (atherosclerosis) and the accumulation of arterial plaque which can lead to heart attacks and stroke. 6 of 7 trials reported 25 – 54% reductions in CRP concentrations in those supplementing with fiber. Another trial, which followed 3,428 men (aged 60 – 79) over the course of 7 years, found that higher fiber intake not only reduced CRP levels, but also lowered other inflammatory markers (interleukin-6 [IL-6]), decreased fat build up in the liver and appeared to reduce the risk of developing diabetes. (6,7,8)
- Elevated Cholesterol – Adding fiber supplements to conventional cholesterol lowering therapy (statin medications) has an additive effect and results in greater reductions in total cholesterol, LDL cholesterol and Apo B. Since I’m not a supporter of statin medications, I was relieved to learn that this same form of fiber (hydroxypropylmethylcellulose – HPMC) can effectively lower cholesterol without any pharmaceutical assistance as well. Other forms of fiber, such as beta glucans derived from oats, are also effective in improving lipid profiles. (9,10,11)
- Metabolic Syndrome and Diabetes – Out of control blood sugar is a major health threat which contributes to many medical conditions. Including plenty of fibrous food and supplements in one’s daily routine can help temper post meal blood sugar response. In essence, it slows the digestion of carbohydrates and simple sugars. This is in turn helps to support arterial function and blood flow which is impaired by a poor diet that promotes cardiovascular disease. One of my favorite studies of late involves a group of American Samoans who replaced their “modern eating habits” with a traditional Samoan meal plan (rich in coconut, fish and various sources of “plant-based fiber”). This dietary shift resulted in numerous heart-healthy changes: an increase in HDL “good” cholesterol, reduced abdominal fat and metabolic syndrome risk factors (elevated blood lipids, high blood pressure and insulin and mid-section obesity). (12,13,14,15,16,17,18)
Chronic Inflammation Impacts Cardiovascular Health and More
- Weight Management – Over the last few years, numerous studies have determined that pre-loading with fiber or consuming more fiber rich foods tends to decrease appetite and promote a healthier weight. Obesity is one of the strongest established risk factors associated with cardiovascular disease. Consuming dietary fiber can promote feelings of satiety by expanding in the stomach (creating a full feeling), calming blood sugar response to food and even modifying the levels of gut hormones that relay hunger and satisfaction signals to the brain. (19,20,21,22,23,24)
There are likely to be other factors involved in the fiber-heart connection. For instance, it was recently noted that high fiber diets were inversely related to an unhealthy thickening of the arteries or carotid intima-media thickness. One theory why is that dietary roughage appears to help regulate calcium levels in the body. Calcium build up in the arteries is now believed to be a major factor in the progression of cardiovascular disease. Those who do not have significant calcium accumulation in the circulatory system appear to be at very low risk of having a heart attack or stroke. (25,26,27,28,29)
The statistics at the beginning of this column are certainly cause for alarm. Heart disease is, in fact, a real threat to worldwide wellness. But what’s also true is that most of the risk factors for cardiovascular disease seem to be modifiable. Thankfully, many of these necessary changes are available to us all. They don’t require a doctor’s prescription pad or a high tech hospital to proceed. But as with all things in life, there are trade-offs. Changing diet and living a protective lifestyle requires a conscious effort. I hope the evidence presented today will provide you with the necessary incentive to make that effort and reap the rewards that I believe it will bring. (30)
Update: December 2010 – The positive news about dietary fiber and cardiovascular disease continues its forward march. New research presented in three separate medical journals helps to bolster the case for including more roughage in your diet in relation to heart health. The December issue of Applied Physiology, Nutrition and Metabolism describes how the addition of soluble fiber to fruit juice can lead to meaningful changes in body fat percentage, body weight and waist circumference in obese individuals. The supplemental fiber appears to accomplish this feat by improving glucose metabolism. As a bonus, the added fiber also resulted in a reduction in LDL (“bad”) cholesterol and triglycerides and a welcome elevation in HDL (“good”) cholesterol. Two other publications in the journals Magnesium Research and Nutrition offer up an indirect pathway by which dietary fiber may improve cardiovascular wellness: by simultaneously increasing magnesium intake. Recent findings indicate that choosing foods that are rich in fiber also tends to elevate dietary exposure to heart-friendly minerals including magnesium. A large body of evidence suggests that a lack of this essential mineral can lead to chronic inflammation which can damage the heart. (31,32,33)
Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!
Tags: Cholesterol, Fiber, High Blood Pressure
Posted in Food and Drink, Heart Health, Nutrition
January 3rd, 2011 at 10:52 am
Many people are unaware of this important information and therefore do not include more and more diatary fiber in their meals.
January 3rd, 2011 at 3:42 pm
Here’s hoping this column helps get the word out. I’m big advocate of including plenty of fiber in most diet plans. Thank you, Pradip!
July 22nd, 2012 at 2:21 pm
It is nice to know you are against “statins”, I have been sensitive to ALl, therefore I do not accept any scripts for them.
Fiber is the answer for sure,better to have a good diet than to have the myalgia caused by Statins!
This article is excellent! Thank you for sharing your knowledge…
March 15th, 2015 at 4:25 pm
Update: Diets rich in fiber reduce excessive inflammation in overweight adolescents …
Pediatr Obes. 2015 Mar 2.
Dietary fibre linked to decreased inflammation in overweight minority youth.
OBJECTIVE: The objective of this study was to examine the relationship between diet and inflammation, and adiposity in minority youth.
DESIGN AND METHODS: The study was designed as a cross-sectional analysis of 142 overweight (≥85th body mass index percentile) Hispanic and African-American adolescents (14-18 years) with the following measures: anthropometrics, adiposity via magnetic resonance imaging, dietary intake via 24-h dietary recalls, and inflammation markers from fasting blood draws utilizing a multiplex panel. Partial correlations were estimated and analysis of covariance (ancova) models fit to examine the relationship among dietary variables, inflammation markers and adiposity measures with the following a priori covariates: Tanner stage, ethnicity, sex, total energy intake, total body fat and total lean mass.
RESULTS: Inference based on ancova models showed that the highest tertile of fibre intake (mean intake of 21.3 ± 6.1 g d-1 ) vs. the lowest tertile of fibre intake (mean intake of 7.4 ± 1.8 g d-1 ) was associated with 36% lower plasminogen activator inhibitor-1 (P = 0.02) and 43% lower resistin (P = 0.02), independent of covariates. Similar results were seen for insoluble fibre. No other dietary variables included in this study were associated with inflammation markers.
CONCLUSIONS: These results suggest that increases in dietary fibre could play an important role in lowering inflammation and therefore metabolic disease risk in high-risk minority youth.
March 20th, 2015 at 1:37 pm
Update: Higher fiber diets linked to lower mortality risk …
Am J Clin Nutr. 2014 Dec;100(6):1498-507.
Fiber intake and all-cause mortality in the Prevención con Dieta Mediterránea (PREDIMED) study.
BACKGROUND: Few observational studies have examined the effect of dietary fiber intake and fruit and vegetable consumption on total mortality and have reported inconsistent results. All of the studies have been conducted in the general population and typically used only a single assessment of diet.
OBJECTIVE: We investigated the association of fiber intake and whole-grain, fruit, and vegetable consumption with all-cause mortality in a Mediterranean cohort of elderly adults at high cardiovascular disease (CVD) risk by using repeated measurements of dietary information and taking into account the effect of a dietary intervention.
DESIGN: We followed up 7216 men (55-75 y old) and women (60-75 y old) at high CVD risk in the Prevención con Dieta Mediterránea (PREDIMED) trial for a mean of 5.9 y. Data were analyzed as an observational cohort. Participants were initially free of CVD. A 137-item validated food-frequency questionnaire administered by dietitians was repeated annually to assess dietary exposures (fiber, fruit, vegetable, and whole-grain intakes). Deaths were identified through the continuing medical care of participants and the National Death Index. An independent, blinded Event Adjudication Committee adjudicated causes of death. Cox regression models were used to estimate HRs of death during follow-up according to baseline dietary exposures and their yearly updated changes.
RESULTS: In up to 8.7 y of follow-up, 425 participants died. Baseline fiber intake and fruit consumption were significantly associated with lower risk of death [HRs for the fifth compared with the first quintile: 0.63 (95% CI: 0.46, 0.86; P = 0.015) and 0.59 (95% CI: 0.42, 0.82; P = 0.004), respectively]. When the updated dietary information was considered, participants with fruit consumption >210 g/d had 41% lower risk of all-cause mortality (HR: 0.59; 95% CI: 0.44, 0.78). Associations were strongest for CVD mortality than other causes of death.
CONCLUSION: Fiber and fruit intakes are associated with a reduction in total mortality.
May 29th, 2015 at 5:51 pm
Nutrients. 2015 May 26;7(6):3959-3998.
Apples and Cardiovascular Health-Is the Gut Microbiota a Core Consideration?
There is now considerable scientific evidence that a diet rich in fruits and vegetables can improve human health and protect against chronic diseases. However, it is not clear whether different fruits and vegetables have distinct beneficial effects. Apples are among the most frequently consumed fruits and a rich source of polyphenols and fiber. A major proportion of the bioactive components in apples, including the high molecular weight polyphenols, escape absorption in the upper gastrointestinal tract and reach the large intestine relatively intact. There, they can be converted by the colonic microbiota to bioavailable and biologically active compounds with systemic effects, in addition to modulating microbial composition. Epidemiological studies have identified associations between frequent apple consumption and reduced risk of chronic diseases such as cardiovascular disease. Human and animal intervention studies demonstrate beneficial effects on lipid metabolism, vascular function and inflammation but only a few studies have attempted to link these mechanistically with the gut microbiota. This review will focus on the reciprocal interaction between apple components and the gut microbiota, the potential link to cardiovascular health and the possible mechanisms of action.
November 10th, 2016 at 12:52 pm
Nutrients. 2016 Nov 7;8(11).
A Prospective Study of Different Types of Dietary Fiber and Risk of Cardiovascular Disease: Tehran Lipid and Glucose Study.
BACKGROUND AND AIM: This study was designed to examine the hypothesis that dietary of intake different types of fiber could modify the risk of cardiovascular disease (CVD) in a large prospective cohort among Iranian adults.
METHODS: In 2006-2008, we used a validated food frequency questionnaire to assess dietary fiber intake among 2295 health professionals with no previous history of heart disease. Subjects were subsequently followed until 2012 for incidence of CVD events. Multivariate Cox proportional hazard regression models, adjusted for potential confounders were used to estimate the risk of CVD across tertiles of total dietary fiber and different types of fiber. Linear regression models were also used to indicate the association of dietary fiber intakes with changes of cardiovascular risk factors during the follow-up.
RESULTS: Mean age of participants (42.8% men) was 38.2 ± 13.4, at baseline. Mean (SD) dietary intake of total fiber was 23.4 (8.9) g/day. After adjustment for cardiovascular risk score and dietary confounders, a significant inverse association was observed between intakes of total, soluble and insoluble dietary fiber and CVD risk, in the highest compared to the lowest tertiles (HR = 0.39, 95% CI = 0.18-0.83, HR = 0.19, 95% CI = 0.09-0.41, and HR = 0.31, 95% CI = 0.14-0.69, respectively). Inverse relations were observed between risk of CVD and dietary fiber from legumes, fruits and vegetables; however, dietary fiber intake from grain and nut sources was not related to risk of CVD.
CONCLUSION: Our findings confirmed that higher intakes of dietary fiber from different sources is associated with CVD events and modify its major risk-related factors.