November,
2006
Osteoarthritis
— Managing “Growing Pains” Through Diet and
Lifestyle
By Mary Kaye Sawyer-Morse, PhD, RD, LD
Today’s Dietitian
Vol. 8 No. 11 P. 28
Bone up on joint health and how proper nutrition,
exercise, and weight control can aid in osteoarthritis symptom
relief.
The symptoms sound familiar: You experience
joint stiffness and pain when you get out of bed in the morning.
You mentally shrug and attribute the discomfort to a busy weekend
of gardening and yard work. You are, after all, getting older
and everyone gets a touch of arthritis.
Although we tend to associate it with the joint
stiffness, aches, and pains of older adults, arthritis affects
people of all ages. In fact, it is the leading cause of disability
among those over the age of 15 in the United States.
So what exactly is arthritis? There isn’t
one answer because arthritis involves a group of diseases, each
with its own cause, symptoms, and treatments. What these diseases
have in common is that they affect some part of the joint; they
cause pain and potential loss of movement and often include
some level of inflammation. The word arthritis, which literally
means joint inflammation, comes from the Greek words arthros
(joint) and itis (inflammation). According to the Arthritis
Foundation, more than 43 million Americans—nearly one
in six—suffer from the more than 100 types of arthritis.
However, a bit of creaky joint stiffness is
a visitor who knocks on nearly everyone’s door sooner
or later. This visitor is often a type of arthritis called osteoarthritis
(OA).
The Basics of OA
OA is the most prevalent type of arthritis, afflicting more
than 21 million Americans, most of whom develop the disease
after the age of 45. With the aging of our population, the condition
is becoming increasingly prevalent.
Diagnosis
Simply put, OA is the painful result of cartilage breakdown.
When the tough, resilient substance that cushions bone ends
no longer does its job effectively, the bones don’t glide
across each other easily within the joint. Therefore, pain and
stiffness set in and knees ache or shoulders stiffen. An OA
diagnosis usually includes a review of physical findings, including
bone tenderness, joint enlargement, decreased range of motion,
and radiographic changes. Radiographic findings in OA frequently
include osteophyte (an outgrowth of bone that is usually found
around a joint) formation, joint space narrowing, and cysts.
Individuals with early OA typically experience
localized joint pain that worsens with activity and gets better
with rest, while those with more severe disease may have pain
even when at rest. In addition, weight-bearing joints may “lock”
or “give way” due to internal derangement, another
consequence of the disease.1
Causes
So what causes cartilage to deteriorate? Sometimes we don’t
know. When that is the case, the condition is called primary
osteoarthritis or osteoarthritis of unknown cause. Other times
the condition can be linked to a specific health problem or
issue and is known as secondary osteoarthritis.
The principal cause of primary OA is unidentified.
For unknown reasons, the collagen network of the cartilage becomes
jumbled; it weakens and is unable to hold its structure. As
the collagen network disintegrates, proteoglycans found in all
connective tissue are released and with them their water-retaining
abilities. The loss of proteoglycans causes the cartilage to
dry out and, over time, even crack. At the same time, the released
proteoglycans draw excess fluid into the joint capsule, causing
swelling.1
In contrast, the cause of secondary OA is usually
straightforward. It results from various types of joint trauma—from
sudden, high-velocity damage (such as a car accident) to small,
repetitive insults to the joints. Specific causes of secondary
OA include the following:
• Repetitive motion injury. Joints stressed
over and over again in the same way are more likely to experience
a cartilage breakdown.
• Joint injury. Once a joint has been
injured, whether through sports or a car accident, it is much
more likely to develop OA.
• Bone disease. A bone disease, such as
Paget’s disease, weakens the bone structure, making it
more likely to fracture and develop bony overgrowth.
• Obesity. The heavier the person, the
more stress the joints must bear. OA of the knee has been clearly
linked to excess body weight.2
Risk Factors
How is it that some individuals experience multiple aches and
pains and others never do? Specific risk factors for OA development
have been identified and include the following:
• Age. OA typically develops after the
age of 45. Like many other tissues, cartilage and other joint
structures tend to degrade and become weaker over time. After
years of use, they start to wear out. However, research has
shown that OA is not inevitable as we age, but the odds do increase.
• Joint injury. Whether from a car accident
or through a sports activity, injury increases the likelihood
of OA development in affected joints.
• Repetitive joint stress. Anyone who
overuses and repeatedly stresses a joint or joints can experience
cartilage breakdown.
• Gender. Women are three times more likely
than men to develop OA. The specific reason is unclear; it may
be due to smaller joint structures or linked to estrogen.
• Genetics. There appears to be a genetic
component to OA.
• Weight. Excess weight increases the
risk of OA development.
Lifestyle as a Treatment
Approach
Your patient or client is ready to take action. The individual
has a confirmed diagnosis of OA and wants a treatment plan that
will alleviate symptoms and keep joint degradation to a minimum.
What’s the next step? Treatment approaches usually consist
of a combination of options, including medication use, both
prescription and over-the-counter remedies; joint protection
techniques and devices; and self-help skills. For more information
on these options, see the listed resources.
Treatment also includes lifestyle approaches
such as exercise, weight control, and diet. More discussion
on these effective approaches follows.
Exercise
For many years, the belief was that if you have arthritis, you
should not exercise because it will damage the joints. Now,
research has convincingly demonstrated that a lack of regular
vigorous physical activity nearly doubles a patient’s
risk for functional decline and eventual disability.3 In fact,
researchers have found that expected two-year rates of functional
decline in older patients with arthritis could have been reduced
by up to 32% with regular physical activity.
What type of activity is recommended? The program
that is best depends on which joints are affected by OA and
the severity of involvement. An exercise program can be designed
for every individual. Patients should always consult their physician
before beginning a program to determine what type of exercise
is appropriate. Additionally, a physical therapist can help
by conducting an assessment of specific exercise and joint protection
needs.
Overall, an exercise program should offer a
balance of three types of activity: flexibility (stretching,
range-of-motion), strengthening (resistance), and cardiovascular
(aerobic) exercises and can include many others, such as walking,
yoga, and playing golf. It’s a matter of finding the best
fit for personal needs, abilities, and interests.
Weight Loss
Being overweight by only 10 pounds increases the force on the
knee by 30 to 60 pounds with each step. Without a doubt, being
overweight increases the load placed on the joints such as the
knee, which increases stress and could possibly hasten the breakdown
of cartilage. However, there is an unidentified connection between
being overweight and OA because overweight is also associated
with higher rates of hand OA in some studies.4 This suggests
the involvement of a circulating systemic factor as well.
Overall, the numbers are compelling: Overweight
women have nearly four times the risk of knee OA; for overweight
men, the risk is five times greater.5 Population-based studies
have consistently shown a link between overweight or obesity
status and development of knee OA.5
Clearly, being overweight is a risk factor for
developing OA. If obesity increases the risk of OA development,
does weight loss help reverse the effects?
Research has demonstrated that in persons who
are obese, losing as little as 15 pounds is associated with
nearly 50% improvement in knee OA symptoms.6 In The Framingham
Study, researchers found that among women with a baseline body
mass index greater than 25, weight loss was associated with
a significantly lower risk of knee OA. Furthermore, investigators
have concluded that individuals who lose enough weight to move
from the obese to the overweight category decrease their risk
of knee OA by nearly 22%.7
It is interesting to note that the Arthritis,
Diet, and Activity Promotion Trial found that the combination
of modest weight loss plus moderate exercise provided better
overall improvements in measures of mobility and pain than either
the diet- or exercise-only groups.6
Diet
The idea that diet is related to arthritis is not new. For hundreds
of years, physicians have “prescribed” various food-related
treatments—such as cod liver oil, severe restriction of
calories, and coffee enemas—for treatment of arthritis.
While much is still under debate, research has shown that diet
plays a valuable role in OA treatment plans.
Vitamin C
Nearly 20 years ago, The Framingham Osteoarthritis Study came
forward through the now famous Framingham Heart Study.7 What
the researchers observed was that the progression of OA was
reduced by more than one half in people who consumed an average
of at least 152 milligrams of vitamin C per day.
Researchers theorize that vitamin C helps reduce pain through
two pathways. First is its role in the formation of collagen
and proteoglycans. Second is its role as an antioxidant. Free
radicals, highly reactive and unstable compounds produced by
the body, can destroy cartilage and disrupt its structure. As
damage occurs, inflammation is produced. Inflammation is part
of an immune response in cartilage; vitamin C is thought to
be beneficial by neutralizing free radicals before they have
an opportunity to destroy cartilage.
Research has continued to explore the therapeutic
role vitamin C may play in OA. Overall, the findings to date
have been mixed. While some studies have shown beneficial effects,
others have not.8 The current advice is that vitamin C intake
not be supplemented above the recommended dietary allowance.
Vitamin D
Additional findings from The Framingham Study showed that vitamin
D is also important with regard to OA. Individuals with knee
OA who consumed less than 350 international units of vitamin
D per day had a threefold to fourfold greater risk for disease
progression than those who consumed 400 international units
or more per day.7
Bone is not structurally normal in OA; there is evidence of
increased turnover and decreased bone mineral content and stiffness.
Vitamin D is crucial for bone strength and structure. It may
also play a direct role in cartilage itself through the chondrocytes.
Even though there is a compelling biologic rationale for supplementation
with vitamin D, as with vitamin C, there are conflicting results
for its role in OA progression.9 Further study is underway.
Omega-3 Fatty Acids
Different types of oils contain different types of fatty acids.
The fatty acids that are consumed make their way into the membrane
of every cell in the human body, including the cells in the
joints. Indeed, the fatty acid makeup of the cell membranes
is a direct reflection of the fatty acids consumed. This is
an important fact with regard to inflammation. The reason is
that fatty acids are precursors of compounds called prostaglandins,
some of which suppress inflammation and some of which support
it. Research has provided considerable evidence that consumption
of omega-3 fatty acids leads to the creation of anti-inflammatory
prostaglandins.10
Eating to Beat Arthritis
To summarize, the nutrition professional can help all persons
with OA understand and apply the benefits of a healthy, well-balanced
diet. Specifically, a dietary approach to help control OA symptoms
includes the following:
• Adequate water. Most individuals need
an average of 8 cups of fluid (preferably water) per day.
• An abundance of vegetables and fruits.
It is important to include three or more daily servings of both
fruits and vegetables. They are the primary food groups that
contain substantial amounts of vitamin C and other important
nutrients that people with OA need.
• A selection of whole grain products.
Whole grains are much richer in certain key nutrients—and
fiber—than processed grains.
• A selection of vegetable proteins as
well as animal proteins. By choosing more vegetable proteins—such
as tofu, beans, nuts, and seeds—the intake of omega-3
fatty acids increases. Cold-water fish, a rich source of omega-3
fatty acids, should also be included. Certain large predatory
fish such as shark, swordfish, king mackerel, and tilefish are
restricted or avoided due to potential toxicity concerns.
• Limited sweets, snack foods, and salty
treats are OK, but they should not be dietary mainstays.
• A focus on healthy fats and oils. Emphasize
the use of canola and olive oil in food preparation.
Good nutrition can be challenging for patients
with OA. The nutrition professional plays a vital role in educating
clients about the importance of a healthy, balanced diet in
controlling OA symptoms.
— Mary Kaye Sawyer-Morse, PhD, RD,
LD, is a professional speaker, an author, and a wellness expert.
She is owner and education director of The Center for Success,
a Texas-based company that provides keynotes, in-service training,
and seminars to diverse industries.
References
1. Howell DS, Altman RD, Buckwalter JA, et al. Osteoarthritis:
Diagnosis and Medical/Surgical Management, 2nd ed., Philadelphia:
W.B. Saunders Company Harcourt Brace Jovanovich, Increase; 1992:761-762.
2. Oliveria SA, Felson DT, Reed JI, et al. Incidence
of symptomatic hand, hip, and knee osteoarthritis among patients
in a health maintenance organization. Arthritis Rheum. 1995;38(8):1134-1141.
3. Shih M, Hootman JM, Kruger J, et al. Physical
activity in men and women with arthritis National Health Interview
Survey, 2002. Am J Prev Med. 2006;30(5):385-393.
4. Felson DT. Weight and osteoarthritis. Am
J Clin Nutr. 1996;63(3 Suppl):430S-432S.
5. Creamer P, Hochberg MC. Osteoarthritis. Lancet.
1997;350(9076):503-508.
6. Messier SP, Loeser RF, Miller GD, et al.
Exercise and dietary weight loss in overweight and obese older
adults with knee osteoarthritis: The Arthritis, Diet, and Activity
Promotion Trial. Arthritis Rheum. 2004;50(5):1501-1510.
7. Felson DT, Anderson JJ, Naimark A, et al.
Obesity and knee osteoarthritis. The Framingham Study. Ann Intern
Med. 1988;109(1):18-24.
8. McAlindon TE, Jacques P, Zhang Y, et al.
Do antioxidant micronutrients protect against the development
and progression of knee osteoarthritis? Arthritis Rheum. 1996;39(4):648-656.
9. Demarco PJ, Constantinescu F. Does vitamin
D supplementation contribute to the modulation of osteoarthritis
by bisphosphonates? Arthritis Rheum. 2005;52(5):1622-1623.
10. Connor WE. Importance of omega-3 fatty acids
in health and disease. Am J Clin Nutr. 2000;71(suppl):171S-175S.
A Closer Look at Cartilage
Articular cartilage acts as a pad between the surfaces of two
bones; it prevents the bones from making contact.
Connective tissue is composed of water, fibroblasts,
chondrocytes, and the substances made by these cells: collagen
and proteoglycans. By weight, connective tissue is comprised
of 60% to 80% water. Water and proteoglycans enable connective
tissue structures to be strong, shock absorbing, and somewhat
flexible.
Chondrocytes are responsible for the formation,
maintenance, and repair of articular cartilage. They break down
and dispose of old proteoglycan and collagen molecules and facilitate
the formation of new ones to take their place.
Collagen is the most abundant protein in the
human body, making up approximately 30% of all proteins. It
is connective tissue that helps hold bones, muscles, and other
bodily structures together. Collagen has a meshlike framework
that provides a structure to house the proteoglycans.
Proteoglycans are large, oblong-shaped, highly
viscous protein molecules that weave themselves securely into
the collagen mesh. They provide much of the shock-absorbing
properties of cartilage.
— MKSM
Resources
Arthritis Foundation, www.arthritis.org
Centers for Disease Control and Prevention,
www.cdc.gov/arthritis
Johns Hopkins Arthritis Center, www.hopkins-arthritis.org
National Institute of Arthritis and Musculoskeletal
and Skin Diseases, www.nih.gov/niams
National Institute of Health Osteoporosis and
Related Bone Diseases — National Resource Center, www.osteo.org
