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Nutrition
101 Home Fundamentals
of Nutrition
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Physiology
of Nutrition
Lecture Series
Lecture
1
Lecture
2
Lecture
3
Lecture
4
Lecture
5
Lecture
6
Lecture
7
Lecture
8
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Lecture 5
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Health
Implications of Obesity
In
1985, a National Institutes of Health Consensus Conference declared that
obesity was a disease with significant health implications. In June 1998,
the National Heart Lung and Blood Institute issued its Guidelines for
the Evaluation and Treatment of Obesity in which a task force reported
on its review of over 300 randomized trials demonstrating the impact of
obesity on some of the most important health problems in our nation and
the world.
1. Heart Disease
and Hyperlipidemia
Increased
production of VLDL particles and decreased clearance of LDL particles
are both associated with mild obesity. Some severely obese subjects have
normal cholesterol levels, and the prevalence of hyperlipidemia is only
about 10% in the severely obese (BMI > 40). Only about 5 % of all hypercholesterolemia
is accounted for by defined genetic hyperlipidemias, other than common
hypercholesterolemia which is a heterogeneous disease. There are 56 million
Americans with cholesterol levles >200 mg/dl and 37 million with cholesterol
levels greater than 240 mg/dl. Only about 3 to 4 million Americans are
taking cholesterol lowering drugs, and one million Americans have heart
attacks each year. It is clear that obesity caused by overnutrition is
the major environmental stimulus to increased cholesterol levels.
2. Diabetes Mellitus
Diabetes
mellitus (sweet urine) is the tip of the iceberg of a genetic-environmental
condition characterized by obesity in greater than 80% of all patients.
Recently, the criteria for diagnosis have been changed from a fasting
blood sugar of >140 mg/dl to >126 mg/dl. The standard medical approach
to the diabetic is to make the diagnosis of the disease and send the patient
to a nurse to learn glucose monitoring, to a dietitian to be taught an
exchange diet, and to a pharmacist to receive pharmacotherapy (oral agents
or insulin) for their diabetes. Throughout this process there has been
no consideration of the primacy of hyperinsulinemia due to excess visceral/abdominal
fat. In the nutritional medicine approach, if there is no infection present
or surgery planned, then glucose control must be secondary to the attempts
to lose visceral fat and increase muscle mass. In fact, over 80% of all
patients receiving insulin never attain normal blood glucose levels. Moreover,
both insulin and oral agents increase appetite leading to weight gain
and undercutting attempts at weight management. Type II diabetes mellitus
is a multifactorial genetic disease which is strongly associated with
obesity. Even small amounts of upper body fat (e.g. 20 pounds) can lead
to insulin resistance and hyperinsulinemia. Weight loss and caloric restriction
benefit the majority of type II diabetics.
3.Common
Forms of Cancer
The American Cancer
Society, in a study of over 750,000 individuals, developed evidence that
obesity contributes to the high incidence of breast, colon, prostate,
uterine, ovarian, pancreatic, gallbladder, and kidney cancer in the United
States. International migration studies demonstrate that when individuals
move from Japan to the U.S., their incidence of breast or prostate cancer
goes up five-fold within one generation. Microscopic cancers (called carcinoma
in situ or latent cancers) are found with increasing frequency in autopsies
of individuals dying of other causes as they age. In fact, aging is the
most important risk factor for cancer. Individuals in Japan and the U.S.,
have the same incidence of latent prostate and breast cancers, but these
grow to be clinically detected five times more frequently in the U.S.
than in Japan. In animals, the growth rate of chemically-induced cancers
can be influenced strongly by changes in diet and exercise. Based on this
evidence, it is believed that there is a growth-promoting effect of our
diet and lifestyle based on the hormones associated with obesity (increased
peptide growth factors and reproductive hormones) and the presence of
pro-oxidant growth-promoting lipids (linoleic acid) in excess. Antioxidants
and the gene-nutrient interaction in cancer promotion will be discussed
later in the course.
4. Hypertension
The majority
of hypertensive patients have mild hypertension with a diastolic blood
pressure of 90 to 95 mm Hg. According to all the step-care approaches
endorsed by medical organizations, diet, exercise, and lifestyle change
are the first steps in treatment. However, the standard medical treatment
is to use an antihypertensive drug. In fact, many patients with mild obesity-associated
hypertension will normalize in the first two weeks of obesity treatment.
"Give Us A Week We’ll Take Off the Weight!" The first weight
loss is due in large part to urinary losses of water and sodium chloride
(2 lb./quart). The amount can be estimated from extrapolating backwards
from the rate of true fat and lean loss after the initial diuresis. Insulin
levels decrease rapidly with calorie restriction and this accounts for
the loss of water since insulin is a sodium-retaining hormone. However,
it should be remembered that hypertension returns with weight gain, so
that the reduction and discontinuation should be done conservatively in
some patients with a strong message indicating the relationship of blood
pressure and weight gain. Increased insulin production is associated with
increased production of catecholamines which can promote hypertension.
Insulin also retains sodium via a renal effect, so that salt retention
will also be promoted in patients with upper body obesity and hyperinsulinemia.
5. Psychosocial
Morbidity and Mortality
While
as physicians, we are concerned with the health effects of obesity, there
are major impacts of obesity on: disturbed family interactions, job performance
and status, self-esteem, and sexuality. These impacts can be utilized
to motivate and reinforce lifestyle changes to treat obesity.
6. Other
Gallstones,
increased surgical morbidity and mortality, and osteoarthritis are associated
with obesity.
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