November 2007
The
Diet-Inflammation Connection
By Sharon Palmer, RD
Today’s Dietitian
Vol. 9 No. 11 P. 38
The emerging science on how diet contributes
to inflammation, thus influencing chronic disease, is big news—especially
for dietitians.
You know something’s big if Oprah covers
it. Yes, the anti-inflammation diet was recent fodder for O,
The Oprah Magazine, so you know it’s
being discussed. Some even speculate that the anti-inflammation
diet will be the next diet craze, which may explain why scores
of books have been written on the subject. A recent Amazon.com
query uncovered 671 books using the search terms “inflammation
and diet.” There’s even The Complete
Idiot’s Guide to the Anti-Inflammation Diet.
“I think that anti-inflammation is sort
of the new buzz word or phrase these days, so I do get a lot
of questions about what it means,” says Lynn Goldstein,
MS, RD, CDN, HHC, a dietitian and holistic health counselor
in New York.
Andrew Weil, MD, director of the Program in
Integrative Medicine of the College of Medicine at the University
of Arizona, put the anti-inflammatory diet on the map thanks
to his popular books, including Healthy Aging: Your
Lifelong Guide to Physical and Spiritual Well-Being,
and Web site, www.drweil.com,
where people can sign up for his Healthy Aging Anti-Inflammatory
Diet.
“People ask about the anti-inflammatory
diet. Dr. Andrew Weil is really getting out there influencing
people,” says Jessica Siegel, MPH, RD, a California Dietetic
Association spokesperson who believes that a healthy, educated,
affluent consumer base is attuned to the issue.
Weil, who spoke at the Nutrition and Health:
State of the Science and Clinical Applications Conference in
San Diego earlier this year, says, “All age-related diseases,
including cancer, have their roots in inflammation. Vascular
disease begins as an inflammatory process, and Alzheimer’s
disease results from inflammation of the brain. You can go through
life in a proinflammatory state or an anti-inflammatory state.
Food choices can either up-regulate inflammation or down-regulate
inflammation.”
Understanding
Inflammation’s Repercussions
Interest in inflammation is flourishing. “Anything in
the inflammation area in the research world is of large interest,
especially in the areas of pain relief,” says Cheryl Reifer,
PhD, RD, LD, director of Sprim USA, an independent research-driven
company focused on health.
“There’s enough evidence to support
that unhealthy characteristics are associated with increased
inflammatory markers to warrant targeted approaches to reduce
inflammation,” says Cynthia Thomson, PhD, RD, an assistant
professor in the University of Arizona’s department of
nutritional sciences. Thomson says a few years ago, scientists
didn’t know whether increased inflammation was linked
to the risk of chronic diseases, but several studies have shown
how diseases such as diabetes and obesity are associated with
increased inflammatory markers. “In diabetes and cancer,
there are more and more studies suggesting that modulation of
inflammatory end points may reduce disease risk,” Thomson
says.
Inflammation is the first organized reaction
to an injurious challenge to the body, whether it’s a
bacterial infection or oxidized low-density lipoprotein cholesterol.
During this process, blood leukocytes migrate to specific tissues,
and leukocytes are activated to guide a series of biochemical
and cellular events. Researchers are discovering that inflammation
is emerging as a root of many chronic diseases. Cardiovascular
disease, the primary diet-related disease of our time, has an
underlying connection to inflammation, as atherosclerosis is
in part due to the accumulation of lipids and inflammatory factors
within the vessel wall.
Inflammation is also a significant component
of obesity, metabolic syndrome, type 2 diabetes, osteoporosis,
periodontal disease, rheumatoid arthritis, neurological degenerative
disorders, and inflammatory bowel disorders. Both epidemiological
studies and intervention trials support a link between the role
of diet and the reduction in the risk of many chronic diseases,
and it appears that creating a proinflammatory milieu may be
one way that unhealthy diets are linked with metabolic and cardiovascular
diseases.
The role that inflammation and oxidative stress
may play in brain aging is of particular interest. Inflammatory
markers, as well as cellular and molecular oxidative damage,
increase during normal brain aging, which is accompanied by
the decline in cognitive and motor performance in older populations,
even in the absence of neurodegenerative diseases. Epidemiological
studies have suggested that diets rich in antioxidant and anti-inflammatory
compounds, such as those found in fruits and vegetables, may
lower the risk of developing age-related neurodegenerative diseases
such as Parkinson’s and Alzheimer’s. Additional
research suggests that the polyphenolic compounds found in fruits
may produce their beneficial effects through signal transduction
and neuronal communication.1-3
Inflammation normally protects against infection,
but when it is ongoing for many years due to infection or hormonal
stimulation, it can lead to excess oxidation and cancer, according
to David Heber, MD, PhD, FACP, FACN, a professor of medicine
and public health and director at the UCLA Center for Human
Nutrition, who also spoke at the conference. In rapidly expanding
abdominal fat cells and many cancer cells, the inflammation
system is turned on all the time, thus leading to the excess
production of cytokines (peptide hormones secreted by inflammatory
cells) and stromal/adipocyte cells that mediate the inflammatory
response. Cytokines are signals that can promote atherosclerosis
and tumor growth.
Connecting the
Dots: Lifestyle and Inflammation
“Through changes in the diet, you can demonstrate improvements
in even low-grade chronic inflammation in people associated
with chronic disease as they age,” says Thomson. A number
of recent studies are looking at various aspects of healthful
eating and how they can reduce markers of increased inflammation.
According to a 2007 review in the Asian
Pacific Journal of Cancer Prevention, C-reactive
protein is one of the acute-phase proteins in inflammation;
thus, high-sensitivity C-reactive protein (hs-CRP) serum concentrations
have intrigued researchers. Studies have linked high concentrations
of hs-CRP and obesity, as well as smoking. Moderate alcohol
consumption and high physical activity have been associated
with low levels of hs-CRP. Many prospective studies have also
found an increased risk of type 2 diabetes associated with high
concentrations of hs-CRP, independent of obesity and other cardiovascular
risk factors, but the findings are inconsistent. Numerous studies
have discovered that high concentrations of hs-CRP are associated
with increased risks of colorectal and other cancers, but these
findings are also inconsistent. High intakes of carotenoids
and vitamin C, but not vitamin E, seem to decrease the level
of circulating hs-CRP. In addition, high consumption of vegetables
and fruits is associated with lower levels of circulating hs-CRP.4
Certain dietary strategies may be associated
with a lower generation of inflammation, according to a state-of-the-art
paper published in a 2006 issue of the Journal of
the American College of Cardiology. Dietary patterns
high in refined starches, sugar, and saturated and trans fatty
acids; low in natural antioxidants and fiber from fruits, vegetables,
and whole grains; and poor in omega-3 fatty acids may cause
an activation of the innate immune system through an excessive
production of proinflammatory cytokines associated with a reduced
production of anti-inflammatory cytokines. The report also notes
that the whole diet approach seems particularly promising in
reducing inflammation associated with the metabolic syndrome.
Choices such as healthy sources of carbohydrate, fat, and protein,
regular physical activity, and avoidance of smoking are critical
to fighting the war against chronic disease. The bottom line
is that the Western way of eating warms up inflammation, and
changing the diet can cool it down.
The results of a 10-week dietary intervention
study involving 17 healthy subjects that was published in 2007
in the European Journal of Clinical Nutrition
found a decreased omega-6/omega-3 polyunsaturated fatty acid
ratio resulted in multiple potentially favorable effects on
the metabolic and inflammatory profiles. And data from the Iowa
Women’s Health Study pointed to a reduction in inflammatory
mortality associated with habitual whole grain intake that was
larger than what was previously reported for coronary heart
disease and diabetes. Because various phytochemicals are found
in whole grains that may directly or indirectly inhibit oxidative
stress and because oxidative stress is an inevitable consequence
of inflammation, the researchers concluded that oxidative stress
reduction by constituents of whole grain is a likely mechanism
for the protective effect.5
The ATTICA epidemiological study, which included
625 men and 712 women with abdominal obesity from the Attica
area in Greece, discovered that among the subjects studied,
low-grade systemic inflammation may be associated with an unfavorable
lifestyle, including physical inactivity and unhealthy dietary
habits, as well as increased blood pressure levels and low high-density
lipoprotein cholesterol.
Send in the Clowns
Even though the field of anti-inflammatory nutrition appears
promising, consumers must brace themselves for questionable
anti-inflammation science. Unfortunately, when the public is
drawn to new diet science, so are the vultures. The anti-inflammatory
diet has already attracted less-than-credible advocates to its
flock. Today, it’s easy to find hundreds of dietary supplements
marketed as reducing inflammation, as well as diets promising
to “reduce toxicity and inflammation in order to lose
10 pounds in seven days and reduce your pain.” Thomson
notes that when new science comes out, “Quacks jump on
board and sell supplements.”
This scenario adds to consumer confusion. “Most
people have no idea what an anti-inflammatory diet is. The most
they usually know is in regards to omega-3 fatty acids because
they have been advertised as having anti-inflammatory properties
all over the place,” says Goldstein. Reifer agrees, noting
that while people are more familiar with antioxidants and omega-3
fatty acids, they are not as familiar with diet and inflammation.
An Anti-inflammation
Diet in Practice
The big question is whether there’s enough science to
support dietary recommendations specifically aimed at reducing
inflammation. Many leading health organizations have yet to
jump on the diet-inflammation bandwagon. Thomson reports that
for many organizations, it may be too soon to establish guidelines
on inflammation and nutrition. “The problem with the science
now is that we haven’t yet determined the most appropriate
study design or inflammatory biomarkers to test dietary effects
and build a consensus,” says Thomson. She urges dietitians
to develop their own evidence base for new science. “You
need to define your own data and knowledge base; nobody should
be your gatekeeper.”
The plain truth is that an anti-inflammatory
diet makes sense. “For example, if you’re telling
people to eat less fat and to increase omega-3 fatty acids and
vitamin D in order to alleviate inflammatory symptoms, there
is little risk of harm. The likelihood of good is real,”
says Thomson. Goldstein paints a picture of an inflammation-reducing
diet to her clients as one that reduces sugar, refined carbohydrates,
saturated fats, and red meat with an increase in fruits and
vegetables, whole grains, legumes, nuts, seeds, lean proteins,
healthy fats such as olive oil, natural healthy spices and seasonings
such as turmeric and garlic instead of salt, and lots of water.
It’s a portrait of a healthy diet straight out of the
rule book.
“I work anti-inflammation into my recommendations,”
says Siegel. “A healthy diet is anti-inflammatory, good
for blood sugar control, heart disease, and cancer prevention.”
Siegel reports that while she doesn’t always use the term
anti-inflammation, dietary recommendations such as omega-6/omega-3
fatty acid balance, minimally processed foods, and more fresh
fruits and plant foods are all part of her recommendations that
cross over into anti-inflammation and wellness.
By focusing on wellness and treating inflammation,
dietitians can experience more opportunities to get away from
disease management and focus on prevention, according to Reifer.
It’s something that can help the entire field of dietetics.
Thomson adds, “Anti-inflammatory dietary counseling should
expand our opportunities for diet intervention. People are likely
to welcome information on how foods have a role in decreasing
the inflammatory response.” Given the burgeoning field
of anti-inflammation before us, it looks like it’s time
to jump in with both feet.
— Sharon Palmer, RD, is a contributing
editor at Today’s Dietitian and a freelance
food and nutrition writer in southern California.
Dr. Weil’s
Eating Plan to Avoid Inflammation
Andrew Weil’s, MD, anti-inflammatory regime is a no-nonsense
approach to eating on which most dietitians would happily place
their stamp of approval. “It really comes down to the
same things I would tell anyone for a healthy diet,” says
Lynn Goldstein, MS, RD, CDN, HHC, a dietitian and holistic health
counselor in New York, of anti-inflammatory diet strategies.
According to Weil, the basic principles of anti-inflammatory
eating include the following:
• Eat a variety of foods.
• Emphasize fresh foods that have better
nutritional quality.
• Avoid processed foods of all kinds.
• Eat an abundance of fruits and vegetables.
• Consume an appropriate number of calories
to maintain optimal weight and metabolic needs.
• Choose less refined carbohydrates with
an emphasis on low glycemic index/glycemic load carbohydrates.
• Focus on whole grains that are truly
“whole,” rather than pulverized and reformulated
(eg, flours and processed breakfast cereals).
• Avoid high fructose corn syrup.
• Decrease consumption of animal proteins,
except fish.
• Increase intake of omega-3 fatty acids.
• Take advantage of whole soy foods.
• Support organic agriculture to avoid
exposure to multiple agents.
• Drink tea instead of coffee.
• Enjoy red wine if alcohol is consumed.
• Consume small amounts of dark chocolate
with a minimum of 70% cocoa.
• Flavor foods with antioxidant spices
such as ginger and turmeric.
• Increase fiber intake through fruits,
vegetables, beans, and whole grains.
• Choose healthy fats by avoiding trans
fats and saturated fats, limiting polyunsaturated fats to maintain
a better omega-6/omega-3 ratio, and emphasizing extra virgin
olive oil, nuts, and avocados.
• Drink more water.
• Consider a multivitamin with mineral
supplement for insurance.
References
1. DeBusk RM, Fogarty CP, Ordoras JM, et al. Nutritional genomics
in practice: Where do we begin? J Am Diet Assoc.
2005;105(4):589-598.
2. Esposito K, Giugliano D. Diet and inflammation:
A link to metabolic and cardiovascular diseases. Eur
Heart J. 2006;27(1):13-14.
3. Lau FC, Shukitt-Hale B, Joseph JA. Nutritional
intervention in brain aging: Reducing the effects of inflammation
and oxidative stress. Subcell Biochem.
2007;42:299-318.
4. Nanri A, Moore MA, Kono S. Impact of C-reactive
protein on disease risk and its relation to dietary factors.
Asian Pac J Cancer Prev. 2007;8(2):167-177.
5. Jacobs DR Jr, Andersen LF, Blomhoff R. Whole-grain
consumption is associated with a reduced risk of noncardiovascular,
noncancer death attributed to inflammatory diseases in the Iowa
Women’s Health Study. Am J Clin Nutr.
2007;85(6):1606-1614.
