Food intolerance as a cause of irritable bowel syndrome
Twenty-one patients with irritable bowel syndrome followed a strict elimination
diet, consisting of a single meat, a single fruit, and distilled or spring
water, for one week. Symptoms disappeared in 14 of the 21 patients. Subsequently,
individual food challenges identified the following symptom-evoking foods
(number of cases in parentheses): wheat (9), corn (5), dairy products (4),
coffee (4), tea (3), citrus fruits (2). Jejunal biopsies were normal in all
nine cases of wheat intolerance, indicating the patients did not have celiac
disease. Six patients underwent food challenges in double-blind fashion through
a nasogastric tube; the food intolerance was confirmed in each case. Changes
in plasma levels of histamine, immune complexes, and eosinophils were similar
after challenge with offending foods and control foods, indicating that these
food intolerances were probably not immunologically mediated. In contrast,
rectal prostaglandin E2 levels increased significantly after challenge with
symptom-evoking foods, but only among patients whose gastrointestinal symptoms
Comment: This study demonstrates that food intolerance is a major factor
in the pathogenesis of irritable bowel syndrome. The reactions to foods may
mediated in part by prostaglandins, but an immunological mechanism does not
appear to be involved. Consequently, the term "intolerance" would
be preferable to "allergy," when describing food-induced symptoms
in patients with irritable bowel syndrome. That distinction is not just academic,
because one would not expect food-allergy testing to provide reliable results
when the problem is not immunologically mediated. At present, an elimination
diet followed by individual food challenges seems to be the most reliable method
of identifying food intolerance.
Jones VA, et al. Food intolerance: a major factor in the pathogenesis of irritable
bowel syndrome. Lancet 1982;2:1115-1117.
Case of the month: heartburn and esophageal reflux
A 28-year-old male presented with a several-year history of heartburn and symptoms
of esophageal reflux. Treatment with various H-2 blockers or proton-pump
inhibitors had controlled the symptoms, but they would recur if he discontinued
these medications. He avoided alcoholic beverages, as they made the problem
worse, but he was not aware of any other symptom-evoking foods or beverages.
Past medical history was negative for colic, recurrent otitis media, eczema,
or other symptoms that might suggest food allergies. Additional questioning
revealed that he ate extremely rapidly, always finishing his meal well before
others at the table did. In the absence of any other obvious cause of his
symptoms, he was advised to chew each bite of food thoroughly. Doing so relieved
his symptoms to the extent that he no longer needed medication.
Comment: In this era of high-tech medicine, we sometimes overlook simple
factors that promote good health. As Upton Sinclair once wrote, "Nature castigates
those who don't masticate." In order to encourage patients to
take time to chew their food, I use the analogy of a 50-pound block of ice
melting on a warm day. Intact, the block of ice would take many hours, or even
days, to melt completely. If chopped into thousands of small pieces, however,
the ice would melt within minutes. In addition to greatly increasing the surface
area exposed to gastric and pancreatic digestive juices, the process of chewing
causes salivary amylase to initiate the digestion of carbohydrates, somewhat
like pouring salt onto the chopped up ice.
Coenzyme Q10 following myocardial infarction
One hundred forty-four patients with acute myocardial infarction were randomly
assigned to receive, in double-blind fashion, 60 mg of coenzyme Q10 (CoQ10)
twice a day or "placebo" (B vitamins providing daily: thiamine
12 mg, riboflavin 12 mg, pyridoxine 4 mg, and niacinamide 100 mg) for one
year. Treatment was begun within 72 hours of the onset of symptoms. Approximately
half of the patients in each group were receiving lovastatin (10 mg/day).
After one year, total cardiac events (24.6 vs. 45.0%; p < 0.02), including
non-fatal infarction (13.7 vs. 25.3%; p < 0.05) and cardiac deaths were
significantly lower in the CoQ10 group than in the control group. The mean
plasma levels of vitamin E (32.4 vs. 22.1 micromol/L) and HDL cholesterol
(1.26 vs. 1.12 mmol/L) were significantly higher (p < 0.05), whereas measures
of oxidative stress (thiobarbituric acid reactive substances, malondialdehyde,
and diene conjugates) were significantly lower, in the CoQ group compared
with the placebo group. The prevalence of fatigue was 40.8% in the CoQ10
group and. 6.8% in the control group (p < 0.01).
Comment: A considerable body of evidence, some conflicting, indicates that
CoQ10 is beneficial for the prevention and treatment of congestive heart failure.
In contrast, the potential value of CoQ10 for secondary prevention of myocardial
infarction has not been systematically studied. The results of the present
study indicate that supplementation with coenzyme Q10 for one year after acute
myocardial infarction significantly reduced cardiac deaths and recurrences
of non-fatal myocardial infarction. In addition, CoQ10 therapy reduced signs
of oxidative stress and decreased the prevalence of fatigue. In a previous
study, supplementation with CoQ10 improved exercise tolerance in patients with
coronary artery disease. Ironically, treatment with statin drugs, which are
used to prevent heart disease, often reduces blood levels of CoQ10, by inhibiting
its synthesis in the body. There is reason to believe that adding CoQ10 to
statin therapy would both enhance the benefits and reduce the side effects
of these drugs.
Singh RB, et al. Effect of coenzyme Q10 on risk of atherosclerosis in patients
with recent myocardial infarction. Mol Cell Biochem 2003;246:75-82.
Probiotic supplement prevents infantile colic
One hundred-eighteen infants (mean age, 7 months) were randomly assigned to
receive, in double-blind fashion, either 1) a standard milk-based formula
containing 1 x 107 colony-forming units (CFU)/g each of Bifidobacterium lactis
and Streptococcus thermophilus, 2) a formula containing 1 x 106 CFU/g each
of B. lactis and S. thermophilus, or 3) unsupplemented formula for a mean
of 210 days. Compared with the unsupplemented formula, each of the supplemented
formulas was associated with a lower frequency of reported colic or irritability
(p < 0.001) and a lower frequency of antibiotic use (p < 0.001). No
significant adverse effects were seen.
Comment: The results of this study demonstrate that long-term consumption
of infant formulas supplemented with B. lactis and S. thermophilus reduced
incidence of colic and irritability, and resulted in a lower need for antibiotics.
Other studies have shown that feeding probiotic organisms to infants or young
children can reduce the incidence of infections and decrease the incidence
or severity of eczema. Probiotics probably work by encouraging the growth of "friendly" intestinal
flora, and possibly by promoting the development of a healthy immune system.
Saavedra JM, et al. Long-term consumption of infant formulas containing live
probiotic bacteria: tolerance and safety. Am J Clin
Fear of frying
In a cross-sectional study of 1,226 people (aged 18-65 years) living in Pizarra,
Spain, the presence of excess concentrations of polar compounds (defined
as > 20%) in home cooking oil was associated with an increased risk of
hypertension (p < 0.01). Of the two main oils available in Spain for cooking,
the use of sunflower oil was associated with an increased risk of hypertension,
whereas the use of olive oil was associated with a decreased risk. These
associations persisted after adjustment for age, gender, obesity, and the
presence of abnormal carbohydrate metabolism. The presence of high concentrations
of polar compounds in cooking oil was presumably due in large part to the
reuse of these oils one or more times for cooking.
Comment: During the process of frying with oils, new compounds are formed as
a result of oxidation, polymerization, and hydrolysis. Polyunsaturated fatty
acids, which are present in relatively large concentrations in sunflower, corn,
and soybean oil, are much more susceptible to thermal degradation than are
monounsaturated or saturated fatty acids, which are present in higher concentrations
in olive oil and peanut oil, respectively. The results of the present study
suggest that repeated heating of vegetable oils that are high in polyunsaturated
fatty acids results in the formation of toxic compounds that increase the risk
of hypertension. By implication, it is probably not a good idea to use these
oils at all for frying. Olive oil and peanut oil appear to be safer oils with
which to fry. While butter and lard do not contain high amounts of unstable
polyunsaturated fatty acids, they do contain cholesterol, which can be converted
to blood vessel-damaging cholesterol oxides during high-temperature cooking.
Soriguer F, et al. Hypertension is related to the degradation of dietary frying
oils. Am J Clin Nutr 2003;78:1092-1097.
Cinnamon beneficial for diabetics
Sixty people (mean age, 52.2 years) with type 2 diabetes who were not on insulin
therapy were randomly assigned to receive cinnamon (1, 3, or 6 g/day) or
placebo for 40 days. Compared with baseline, all three doses of cinnamon
reduced the mean fasting serum glucose (18-29%), triglyceride (23-30%), LDL-cholesterol
(7-27%), and total-cholesterol (12-26%) levels; the responses to all the
doses of cinnamon were similar. No significant changes were noted in the
placebo group. The reductions in mean fasting serum glucose and triglyceride
levels were all significant (p < 0.05) compared with placebo, and some
but not all of the reductions in total- and LDL-cholesterol levels were significant
compared with placebo.
Comment: These results indicate that daily ingestion of a modest amount of
cinnamon (1 g/day or more) significantly reduced serum glucose and triglyceride
levels, and possibly reduced serum total- and LDL-cholesterol levels in patients
with type 2 diabetes. In previous studies, extracts of cinnamon have been shown
to increase glucose uptake in vitro. In addition, cinnamon appears to aid in
triggering the insulin cascade (the series of biochemical actions stimulated
by insulin). Taking cinnamon is an inexpensive and apparently safe way to improve
glucose levels and other metabolic abnormalities that occur in people with
type 2 diabetes.
Khan A, et al. Cinnamon improves glucose and lipids of people with type 2 diabetes.
Diabetes Care 2003;26:3215-3218.
Lactoferrin aids in Helicobacter eradication
Fifty patients with dyspepsia and gastritis who were infected with Helicobacter
pylori were randomly assigned to receive open treatment for one week with
standard triple therapy (rabeprazole, clarithromycin, and tinidazole), either
alone or in combination with lactoferrin (200 mg twice a day). H. pylori
status was assessed eight weeks after the end of treatment by means of the
urea breath test or H. pylori stool antigen test. The eradication rate was
100% (24/24) in the group receiving lactoferrin, compared with 76.9% (20/26)
in the group not receiving lactoferrin (p = 0.023).
Comment: Lactoferrin is a protein present in human and cow's milk
that has bacteriostatic and bactericidal effects against various organisms.
antibiotic effect of lactoferrin has been attributed to its ability to bind
iron, thereby preventing the utilization of iron by bacteria for growth. In
addition, lactoferrin appears to cause adverse changes in bacterial membrane
permeability. The results of the present study indicate that lactoferrin can
be used to increase the eradication rate in patients receiving triple therapy
for H. pylori infection.
Di Mario F, et al. Use of lactoferrin for Helicobacter pylori eradication.
Preliminary results. J Clin Gastroenterol 2003;36:396-398.
Gamma-linolenic acid for dry eyes
Twenty-six patients (mean age, 58.8 years) with dry-eye syndrome (aqueous-deficient
keratoconjunctivitis sicca) were randomly assigned to receive a placebo or
a combination of linoleic acid (57 mg/day) and gamma-linolenic acid (30 mg/day)
orally for 45 days. All patients used substitute tears four times a day.
Compared with placebo, active treatment resulted in a significant improvement
in symptom score (p < 0.005), staining with lissamine green (p < 0.005)
(an objective measure of dryness of the eyes), and ocular surface inflammation
(p < 0.05).
Comment: There is evidence that chronic dry eye disease is caused in part
by inflammation of the lacrimal glands and the ocular surface. Gamma-linolenic
acid (GLA) has anti-inflammatory effects, and has been found previously in
a small clinical trial to relieve dryness of the eyes in people with Sjogren's
syndrome or dryness caused by certain medications. The amount of GLA used in
the present study was small Ð approximately 10-30% of the amount used in
previous studies. A typical 500-mg capsule of evening primrose oil contains
45 mg of GLA. It is unlikely that the linoleic acid used in this study was
responsible for the improvement, since the average diet contains considerably
more linoleic acid than the 57 mg/day given as a supplement.
Barabino S, et al. Systemic linoleic and gamma-linolenic acid therapy in dry
eye syndrome with an inflammatory component. Cornea 2003;22:97-101.