antiinflammatory

Do Whole Grains Reduce Inflammation?

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Are Low Carb Diets Healthy Long Term?

Author: Dr. Stephen Chaney 

InflammationInflammation is a bit like Dr. Jekyll and Mr. Hyde. Acute inflammation plays a valuable role in our immune response. But chronic inflammation is a scourge. Chronic inflammation:

  • Is a key component of all the “itis” diseases.
  • Can lead to autoimmune diseases.
  • Is thought to play an important role in heart disease.
  • Is associated with many other diseases, such as diabetes, cancer, Alzheimer’s disease, and inflammatory bowel diseases (IBS).

While there are many causes of chronic inflammation, diet plays an important role. In a previous issue of “Health Tips From the Professor” I have described how an anti-inflammatory diet can quell the fires of chronic inflammation.

Fiber from unprocessed plant foods is a key component of an anti-inflammatory diet. But are all plant fibers equally effective at reducing inflammation? Here is what we know:

  • Fiber from whole grains, vegetables, and fruits have different chemical and physical characteristics and support the growth of different species of friendly bacteria in our intestines.
  • Previous studies have shown that higher intakes of dietary fiber are associated with lower risk of heart disease.
    • Studies have suggested that fiber from whole grains may be more effective than fiber from fruits and vegetables at reducing heart disease risk.
  • Chronic inflammation is highly associated with the development of heart disease. This has led to the hypothesis that fiber from whole grains may be more effective than other plant fibers at reducing chronic inflammation.
    • Some studies have supported this hypothesis, but they have all been done with middle-aged participants, not with elderly participants who characteristically have higher levels of inflammation.

The study (R Shivakoti et al, JAMA Network Open, 5(3): e225012, 2022) I will describe today was designed to:

  • Test the hypothesis that whole grain fiber is more effective than vegetable or fruit fiber at reducing inflammation.
  • Determine how important reducing inflammation is at reducing the risk of heart disease.
  • Extending these findings to an older population group.

How Was The Study Done?

Clinical StudyThe data for this study was obtained from the Cardiovascular Health Study (CHS), a study designed to characterize factors influencing cardiovascular health in American adults aged 65 years or older. This study analyzed data from 4,125 participants (40% men, 95% white) who enrolled in the CHS study from 1989 to 1990.

These participants did not have heart disease at the time they were enrolled in the study. They had an average age of 72.6 at the beginning of the study and were followed for an average of 11.9 years. During that time 1,941 (47%) of them developed heart disease.

When the participants were enrolled in the study:

  • A food frequency questionnaire was administered to them by a trained dietitian to assess their long-term usual dietary intake. This information was used to assess:
    • Their total fiber intake and…
    • Their fiber intake from various dietary sources (whole grains, vegetables, and fruits).
  • Fasting blood samples were collected and used to analyze various markers of inflammation.

A follow-up via phone was conducted every 6 months to track an initial diagnosis of cardiovascular disease.

At the end of the study, the investigators analyzed:

  • The effect of total fiber and fiber from different food sources on the risk of developing heart disease.
  • The effect of total fiber and fiber from different food sources on inflammatory markers in the blood.
  • The extent to which decreased inflammation could explain the effect of whole grain fiber on reducing heart disease.

Do Whole Grains Reduce Inflammation?

With respect to inflammation:

  • Increased intake of total fiber was associated with healthier levels of the inflammatory markers CRP, IL-1RA, and sCD163.
    • Increased intake of fiber from whole grains was associated with healthier levels of the inflammatory markers CRP, IL-6, and IL-1RA.
    • Increased intake of vegetable fiber was not significantly associated with healthier levels of any inflammatory marker.
    • Increased intake of fiber from fruits was associated with healthier levels of the inflammatory marker sCD163.

With respect to cardiovascular disease:

  • Every 5g/day increase in total fiber decreased the risk of heart disease by 5%.
    • Every 5g/day increase in fiber from whole grains decreased the risk of heart disease by 14%.
    • Increased intake of fiber from vegetables and fruits did not have a statistically significant effect on the risk of heart disease.

Finally, when the investigators did a statistical analysis to determine to extent to which the effect of whole grain fiber on inflammation, could explain its effect on heart disease, they concluded:

  • The effect of whole grain fiber on inflammation could explain only about 16% of its effect on heart disease.

In the words of the authors, “In this prospective study of older adults, higher intakes of total fiber were associated with lower levels of various inflammatory markers, and this inverse association was primarily due to cereal fiber intake. Vegetable and fruit fiber intakes were not consistently associated with lower levels of inflammatory markers. These results suggest that specifically cereal fibers might be more effective in reducing systemic infection, which will need to be tested in interventional studies of specific populations.

In addition, cereal fiber was associated with a lower risk of CVD, although inflammation mediated less than 20% of the observed inverse association between cereal fiber and CVD. This suggests that the association of cereal fiber is primarily due to factors … other than systemic inflammation.”

Note: This conclusion underplays the role of fruit fiber in reducing inflammation. The statement is correct in saying only whole grain fiber reduces the inflammatory markers CRP, IL-6, and IL-1RA. However, both total fiber and fruit fiber increase the anti-inflammatory marker sCD163. That is why I chose to use the term “healthier levels” rather than lower or higher levels when describing the effects of whole grain and fruit fibers on markers of inflammation.

What Does This Study Mean For You?

confusion#1: The biggest takeaway from this study is that whole grains are good for you.

  • This study shows that whole grain fiber decreases our risk of developing heart disease.
    • This is fully consistent with multiple previous studies showing that whole grains decrease the risk of heart disease.
    • Previous studies have also shown that whole grains reduce the risk of cancer and diabetes.
  • This study also suggests that whole grain fiber reduces chronic inflammation.

There are also some takeaways from this and previous studies that may not be so obvious.

#2: Fiber has many important benefits beyond its effect on inflammation. For example:

  • This study concluded that the reduction in inflammation only explained a small part of the beneficial effect of whole grain fiber on reducing heart disease risk.
  • That is because whole grain fiber also:
    • Feeds friendly bacteria that improve gut function.
    • Provides satiety that can result in reduced fat and calorie intake.
    • Binds cholesterol, which improves blood cholesterol level.
    • Slows the rate at which dietary sugar enters the bloodstream, which improves blood sugar control.

#3: Whole plant foods have many benefits beyond their fiber content.

  • This study concluded that whole grain fiber was more beneficial than fiber from fruits and vegetables at reducing inflammation and reducing the risk of heart disease.
  • Previous studies have also shown that fruit and vegetables significantly decrease the risk of heart disease, stroke, and cancer.
  • That is because whole grains and unprocessed fruits and vegetables:
    • Displace sugar, refined flour, and highly processed foods from the diet.
    • Have a lower caloric density than processed foods, making it easier to achieve a healthy weight.
    • Provide nutrients and phytonutrients not found in processed foods.
    • Support a wide variety of healthy gut bacteria.

Are Low Carb Diets Healthy Long Term?

low carb dietconfusionWhen you consider all the benefits of whole grains, fresh fruits, and vegetables, it brings us to the final take home message.

#4: Despite what Dr. Strangelove has told you, low-carb diets may not be healthy long term.

  • There are no long-term (10 or 20-year) studies of low-carb diets. We simply have no evidence to support the claim that they are healthy long term.
  • Most low-carb diets eliminate or severely limit fruits and whole grains. Considering the many health benefits they provide, it is unlikely that any diet that restricts them is healthy long term.

The Bottom Line 

A recent study looked at the effect of plant fiber on inflammation and on heart disease.

With respect to inflammation the study found:

  • Increased intake of total fiber was associated with healthier levels of the inflammatory markers CRP, IL-1RA, and sCD163.
    • Increased intake of fiber from whole grains was associated with healthier levels of the inflammatory markers CRP, IL-6, and IL-1RA.
    • Increased intake of vegetable fiber was not significantly associated with healthier levels of any inflammatory marker.
    • Increased intake of fiber from fruits was associated with healthier levels of the inflammatory marker sCD163.

With respect to cardiovascular disease:

  • Every 5g/day increase in total fiber decreased the risk of heart disease by 5%.
  • Every 5g/day increase in fiber from whole grains decreased the risk of heart disease by 14%.
    1. The biggest takeaway from this study is that whole grains are good for you.

 Other takeaways from this and previous studies are:

2) Fiber has many important benefits beyond its effect on inflammation.

3) Whole plant foods have many benefits beyond their fiber content.

4) Despite what Dr. Strangelove has told you, low-carb diets may not be healthy long term.

For more details on this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Does Time-Restricted Eating Have A Downside?

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Are The Benefits Of Time-Restricted Eating An Illusion?

 Author: Dr. Stephen Chaney

intermittent fastingWeight loss is difficult. If you are like most American adults, you have tried at least 5 or 6 diets by the time you are 50, and all of them have failed. Or maybe you have found a diet that works reasonably well at helping you lose weight, but it’s difficult to stick with. And you worry that it may not be healthy long-term.

But hope springs eternal, and there are always new diets to try. One of the newer diet fads is something called intermittent fasting. The most popular form of intermittent fasting (because it is the easiest to follow) is something called time-restricted eating.

The concept is simple. You don’t change what you are eating. Instead, you restrict the time during which you are eating those foods. Typically, you restrict your time of eating to 8 hours a day and abstain from all food the rest of the day. Hence, the term “time-restricted eating”.

I won’t go into the supposed benefits of time-restricted eating. You have probably heard those already from advocates of this form of eating. But you may be wondering if those benefits are true and whether time-restricted eating has any drawbacks.

Fortunately, a recent study (T Moro et al, Medicine and Science In Sports & Exercise, 53, 2577-2585, 2021) answers those questions. It put a group of athletes on either a control diet or a time-restricted diet for an entire year and looked at the relative benefits and drawbacks of both diets.

How Was This Study Done?

Clinical StudyThis study recruited 19 healthy, resistance-trained males (average age = 29, average weight = 185 pounds) for the study. All the subjects had at least 5 continuous years of resistance training, no steroid use, and no known medical conditions.

The subjects completed a 7-day food diary prior to the study, at the end of 2 months, and at the end of 12 months. The participants were instructed not to change their usual caloric intake or diet composition. In addition, each participant received a personalized diet protocol based on the analysis of their food diary at baseline.

The results from the first two months have previously been reported (T Moro et al, Journal of Translational Research, 14: 290, 2016). This report covers the subsequent 10 months.

During the first two months, the participants were contacted weekly by a dietitian to ensure adherence to the diet. During the interviews, the dietitian asked questions about meal timing and composition, appetite, and any difficulties in maintaining the diet protocol. When necessary, the dietitian gave advice to improve adherence to the diet. During the subsequent 10 months, the participants were contacted less frequently, and the interviews were shorter.

The participants were divided into two groups. The selection was random except that the two groups were matched with respect to caloric intake at baseline (~2,900 calories/day).

The ND (normal meal distribution) group ate their meals over a 12-hour period, with meals at ~8AM, 1 PM, and 8 PM. The distribution of calories for this group was 25%, 40%, and 35% over the three meals.

The TRE (time-restricted eating) group ate their meals over an 8-hour period, with meals at ~1PM, 4 PM, and 8 PM. The distribution of calories for this group was 40%, 25%, and 35% over the three meals.

The training regimen consisted of strength training specifically designed to increase muscle mass. A standardized 3-times per week training regimen was established during the first two months of supervised training. The participants continued the same training regimen on their own for the next 10 months. Workouts were performed between 4 and 6 PM to fall within the eating window for both groups.

Finally, tests for inflammatory markers, cholesterol & other blood lipids, blood sugar control, hormones, body composition, and strength were performed before the program started, at 2 months, and again at 12 months.

What Are The Benefits Of Time Restricted Eating?

thumbs upWhen the investigators looked at health outcomes at the end of 12 months:

  • Inflammatory markers were significantly reduced in the TRE (time-restricted eating) group compared to the ND (normal meal distribution) group.
  • Blood sugar control was significantly improved in the TRE group compared to the ND group.
  • Lipid profiles were significantly improved in the TRE group compared to the ND group.

These results are consistent with the findings of earlier short-term studies on the benefits of time restricted eating.

The authors concluded. “Our results suggest that long-term time-restricted eating in combination with a resistance training program is feasible, safe, and effective in reducing inflammatory markers and risk factors.”

At this point you are probably thinking, “It sounds like everything I have heard about time-restricted eating is true. I can’t wait to get started.”

What Causes The Benefits Of Time-Restricted Eating?

SkepticBefore you jump on the time restricted eating bandwagon, let’s look more closely and ask what caused these apparent health benefits.

When the investigators looked at changes in caloric intake over the 12-month period:

  • The TRE group spontaneously decreased their total caloric intake by 6.4% in spite of being told not to change their diet.
    • The decrease in caloric intake was driven by a decrease in both carbohydrate and fat intake, while protein intake remained constant.
    • Most of this change occurred between 2 and 12 months when they were no longer being closely supervised by dietitians.
  • In contrast, caloric intake and macronutrient intake did not change significantly for the ND group.

The reason for the decrease in caloric intake is not known.

  • If you follow social media or blogs about time-restricted eating, you have been given some scientific-sounding mumbo-jumbo about how the 16 hours of fasting changes your metabolism and/or reduces your appetite. However, this is speculation. There is scant evidence for it.
  • A more likely explanation is that when you restrict the time you allow yourself to eat, you naturally eat less without thinking about it. You are simply less hungry when the second and third meals roll around. [This may explain why even these highly disciplined athletes required weekly coaching by dietitians to keep their caloric intake constant.]

And when the investigators looked at changes in body weight over the 12-month period:

  • The TRE group lost 3.4% of their body weight.
    • Most of that weight loss was due to a decrease in fat mass, but there was also a loss of muscle mass.
  • In contrast the ND group increased their total body weight by 3.4%.
    • In other words, at the end of 12 months the difference between the TRE and ND groups amounted to almost 7% of their body weight. This difference was highly significant.
    • Most of the increase in body weight in the ND group was due to a 2.9% increase in muscle mass.

These results are also consistent with the findings of earlier studies of time-restricted eating.

The observed decrease in body weight and fat mass is important because whenever you decrease body weight and fat mass, you:

  • Reduce inflammatory markers.
  • Improve blood sugar control.
  • Improve lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

Of course, that still sounds pretty good. Who wouldn’t want to lose weight and get healthier? But are the weight reduction and health benefits unique to time-restricted eating? That is the claim of those who promote this diet.

But is it true? To answer that question, we need to take a broader view of popular diets. We need to ask, “Is something special about time-restricted eating, or would other restrictive diets give similar results?”

Are The Benefits Of Time-Restricted Eating An Illusion?

The TruthThere are two diet truths that nobody is talking about:

1) Forget the metabolic mumbo-jumbo. The primary reason restrictive diets cause you to lose weight is that you unconsciously eat less while you are on these diets.

For time-restricted eating, you eat less because you have restricted the time when you can eat. With other restrictive diets, you have restricted the foods you can eat. The reason why that causes you to eat less is more subtle. I call it the “Bagels and Cream Cheese Effect”.

    • When you go on a low-fat diet, it sounds great to say you can eat all the bagels you want. But without the cream cheese, bagels become boring, and you eat less.
    • When you go on a low-carb diet, it sounds great to say you can eat all the cream cheese you want. But without the bagels, cream cheese becomes boring, and you eat less.

2) The proponents of fad diets make them look good by comparing them to the typical American diet. Anything is better than the American diet. However, when you make the comparisons based on the reduction in caloric intake or the amount of weight lost, the health benefits of popular diets are virtually identical. For example:

    • When you compare the Atkins diet and other low carb diets with the typical American diet, inflammation is lower on the low carb diets. However, one recent study compared people on the Atkins diet with people who had lost an equal amount of weight on a balanced diet that included all food groups. Guess what? Inflammation is much higher on the Atkins diet when you compare it to a healthy diet that gives equal weight loss.
    • This study reported that the time-restricted eating group ate less, lost more weight, and had better health parameters than the control group. However, previous studies that compared time-restricted eating with groups that reduced caloric intake to the same extent by simply counting calories have found the two groups had identical weight loss and improvement in health parameters.

In other words, there is nothing magical about time-restricted eating. Any diet that causes you to eat less will give identical results. There are only two questions left:

  1. Can you stick with time-restricted eating long term?

Time-restricted eating is not everyone’s cup of tea. But this study suggests that if you can stick with it better than with other restrictive diets, you are likely to lose weight and reap some health benefits.

2) Should you stick with time-restricted eating long term?

To answer this question, you need to know whether there are any downsides to time-restricted eating.

Does Time-Restricted Eating Have A Downside?

thumbs down symbolOf course, most people would consider weight loss and an improvement in health parameters as a definite plus. It’s all good. Or is it? Does time-restricted eating have any downsides? This study identified two potential downsides:

1) Decreased anabolic hormones.

    • Anabolic hormones (hormones that stimulate an increase in muscle mass) were decreased in the TRE group. Specifically:
      • Testosterone was decreased by 17% at the end of 12 months in the TRE group.
      • Insulin-like growth factor-1 (IGF-1) was decreased by 14% in the TRE group.
    • Both anabolic hormone levels were unchanged in the ND group.

2) Decreased muscle mass. Between months 2 and 12:

    • Muscle mass was decreased by 2.3% in TRE group and increased by 2.9% in the ND group.
    • The cross-sectional area of arm and thigh muscles was decreased by an average of 4.3% in the TRE group and increased by an average of 8.5% in the ND group.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

That is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. So, a continuous increase in muscle mass and cross-sectional area would be expected. This was seen in the ND group but not in the TRE group, which actually lost muscle mass. The average “Joe” or “Jane” would likely lose even more muscle on this diet.

And continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

The Bottom Line 

A recent study looked at the pros and cons of following a time-restricted eating (TRE) diet compared to a diet with normal meal distribution (ND) for 12 months.

  • The TRE group had reduced inflammation, better blood sugar control, and better lipid profiles than the ND group.

However, the improved health parameters were not caused by some magical metabolic changes due to fasting.

  • The TRE group unconsciously reduced their caloric intake and lost weight compared to the ND group. And any time you lose weight, you get reduced inflammation, better blood sugar control, and better lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

And there is nothing unique about time-restricted eating.

  • Any restrictive diet is likely to give similar results. (For more details, read the article above.)

Finally, there were some significant downsides to time-restricted eating.

  • The TRE group had a reduction in anabolic hormones and lost muscle mass.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

This is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. They should have gained muscle mass. Instead, they lost it.

Continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Are Dietary Polyphenols Associated With Longevity?

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Are Polyphenols The Fountain of Youth?

Author: Dr. Stephen Chaney

Merlot Grapes HDRYou’ve probably heard that resveratrol and other polyphenols in red wine can help mice live longer. But what about us? Are dietary polyphenols associated with longevity in humans?

Until recently nobody knew the answer to that question. However, a recent study (Zamora-Ros et al, J. Nutr. 143: 1445-1450, 2013) suggests that polyphenols may just help us live a bit longer.

Of course, the news headlines make it sound like a sure thing, and many of the manufacturers of polyphenol-containing supplements are already citing the study as “proof” that their products will make you live forever.

Polyphenols Are Everywhere:

So, let me give you some background information before I start diving into the study.

  • The term polyphenols includes some names you may recognize, such as flavonoids, isoflavones, anthrocyanidins and resveratrol, and many more that might look like the kind of names you might expect to find on a processed food label.
  • Polyphenols don’t just come from red wine. There are several hundred polyphenols in edible foods. Many fruits, vegetables (including beans like soybeans) and whole grains – the kinds of foods that every expert recommends for a healthy diet – are also great sources of polyphenols.
  • Most polyphenols are excellent antioxidants. Studies suggest that they may also exert antiinflammatory effects and may reduce the risk of heart disease, neurodegenerative disease and cancer. So it is not unreasonable to assume that they might enhance longevity.

An In-Depth Analysis Of The Study:

The study enrolled 807 men and women over the age of 65 (average age = 74, range = 67-81) from the Chianti region of Italy and followed them for 12 years. At the beginning of the study polyphenol intake of the participants was analyzed from a dietary recall form (polyphenol intake based on what they remembered eating) and from a 24 hour urine specimen (actual polyphenol intake).

During the 12 year follow-up, 34% of the participants died. Based on the dietary recall, there was no association between dietary polyphenol intake and mortality. However, based on urinary polyphenol content there was a 30% decrease in mortality for those with the highest dietary polyphenol intake (>650 mg/day) compared to those with the lowest polyphenol intake (<500 mg/day).

Strengths of the Study:

  • This is the very first study to actually investigate the relationship between dietary polyphenols and longevity in a meaningful way. The study was well designed and well executed.
  • The measurement of urinary polyphenol content is a strength of this study. Dietary recalls are often inaccurate. In fact, this study suggests that dietary recalls should probably not be used to estimate dietary polyphenol intake in future studies.

Weaknesses of the Study:

  • This was a first study of its kind, and like any other first study it needs to be confirmed by additional studies.
  • The study only measured associations, not cause and effect. Of course, it would be almost impossible to conduct a double blind, placebo controlled study of this duration – especially if one is using urinary excretion as a measure of polyphenol intake.
  • The study did not report the dietary sources of the polyphenols, although this information was presumably available from the dietary recalls. Because the study was conducted in the Chianti region of Italy it is probably pretty safe to assume that red wine contributed to the polyphenol intake. However, people in that region of Italy also tend to consume diets rich in fruits and vegetables. Hopefully, future studies will help determine whether some polyphenols are more important for longevity than others.

The Bottom Line:

1)     Eat lots of fresh fruits and vegetables. They’ll make you healthier, and you just may live longer.

2)     If you like red wine, drink it in moderation. Just don’t assume that it can substitute for a healthy diet. This study measured total polyphenols, not just red wine polyphenols.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Health Tips From The Professor