Clinical Briefs
With Comments from Russell H. Greenfield, MD. Dr. Greenfield is Clinical Assistant Professor, School of Medicine, University of North Carolina, Chapel Hill, NC; and Visiting Assistant Professor, University of Arizona, College of Medicine, Tucson, AZ.
Cheese-Zits? Dairy and Acne
Source: Adebamowo CA, et al: Milk consumption and acne in teenaged boys. J Am Acad Dermatol. 2008;58:787-793.
Goal: To determine whether there is a significant association between dairy intake and incidence of acne in adolescent boys.
Study Design: Prospective cohort trial (data taken from the Growing Up Today Study [GUTS]).
Subjects: Boys aged 9-15 years at baseline, all participants in the GUTS, who completed the appropriate questionnaires and had plausible data entries regarding energy intakes.
Methods: Subjects completed a 126-item food frequency questionnaire (FFQ) in 1996, and either a 125-item FFQ in 1997 or a 116-item FFQ in 1998. The questionnaires asked how frequently on average participants used a typical portion size of specified foods over the prior year. With reference specifically to milk products, participants were asked whether they drank milk at all, and if so whether the milk were whole, 2%, 1%, skim / nonfat or soy. Nutrient intakes were calculated from answers provided by subjects. Non-dietary information was also collected (height, weight, etc.). In 1999, a specific question was asked of the cohort regarding the frequency of pimples. Dietary responses from 1996 were examined and compared with responses to the 1999 acne question. Association of acne with dietary data from 1997 and 1998 was also evaluated, as were cumulative dietary data from 1996-1998.
Results: Nearly half of all subjects drank whole or 2% milk; 23% drank 1%, 29% skim, 0.4% soy milk, and 3% did not drink milk at all. Almost 80% reported mild acne, while 44% indicated they had experienced more significant outbreaks. Multivariate prevalence ratios (PRs) were 1.16, 1.10, 1.17 and 1.19 for total, whole / 2%, 1% and skim milk, respectively. There was also a weakly positive association between acne occurrence and vitamin D supplementation. There was no association between acne development and intakes of vitamin D or calcium from food, vitamin A, total fat, types of fat, other dairy foods or non-dairy foods. Tanner stage and height were, however, associated with acne prevalence.
Conclusion: There is a mildly positive association between intake of dairy, especially skim milk, and acne in teenaged boys. The findings suggest that milk contains either hormones in sufficient quantity or other factors that can elicit biological effects in humans.
Study strengths: Use of a validated and reproducible FFQ; attention to potential bias; multivariate analysis.
Study weaknesses: Self-assessment of acne with no validation of diagnosis and no information regarding onset of malady; other lifestyle factors, steroid use, and underlying diseases were not considered; over 3,500 boys from the original cohort did not respond to the 1999 questionnaire that contained the acne question.
Of note: The GUTS is an ongoing cohort study of over 9,000 girls and 7,000 boys aged 9-15 years at baseline in 1996 where lifestyle factors are followed annually via questionnaire (the subjects are offspring of women in the Nurses Health Study II cohort); boys in this trial were relatively immature with an average height of only 5 feet, having not yet entered their growth spurt (or peak years of IGF-1 production, important because IGF-1 also increases circulating androgen levels); in this study, dairy foods included not only cheese, milk, ice cream, yogurt and butter, but also instant breakfast drinks, cottage cheese, and chocolate milk; results for whole milk and 2% milk results were combined because the latter retains most of its fat; responses for non-dairy foods were collapsed due to low numbers; most research on diet and acne has focused on girls, with results mostly suggesting a positive association; animal studies point to similar responses from ingested whey protein as seen with androgens; boys who did not respond to the 1999 acne question were, in general, slightly older than responders.
We knew that: Acne is a chronic disease that, while self-limiting, can cause not only physical morbidity but also psychological stress in the upwards of 90% of adolescents and young adults it affects; according to the authors, acne results from "androgen-stimulated hyperkeratinization and subsequent obstruction of the pilosebaceous follicles due to a combination of factors that include failure of normal desquamation of the follicular epithelium, sebum production, colonization of the follicles by Propionibacterium acne and Malassezia species, and inflammation;" milk could influence the development of acne due to the presence of androgens and non-steroidal growth factors, many of which survive processing to be carried by whey protein fractions; in industrialized nations, peak prevalence of acne is between the ages of 16-18 years, with the condition being more common in girls overall, but more common in boys after age 15 years; human and bovine IGF-1 share the same amino acid sequences, and several milk proteins protect IGF-1 from gut digestion.
Comments: While concerns about high dairy intakes have been raised from time to time, and in spite of a growing awareness of other food sources of calcium, dairy products continue to play a pivotal role in many dietary programs. The authors state that "the amount of androgens in milk has generally been considered low, and first-pass metabolism in the liver may further reduce their bioavailability compared with the endogenous production in young children and adolescents." Recent data, however, suggest that dietary factors may be a significant source of hormonally active agents. The results of the current study could create additional uneasiness were it not for the fact that a large proportion of the initial cohort did not fill out their questionnaires, potentially skewing the data. Regardless, additional investigation is warranted to help quell slow-growing fears that regular dairy consumption might negatively impact hormonally-sensitive tissues years down the road. Worded another way (tongue in cheek), what if a daily milk moustache actually helps one grow a real moustache, desired or not? The last word on this topic is yet forthcoming.
What to do with this article: Keep a copy on your computer.
Curried Kidney Stones? Turmeric and Urolithiasis
Source: Tang M, et al: Am J Clin Nutr. 2008;87:1262-1267.
Goal: To quantify total and soluble oxalate content of cinnamon and turmeric, and to evaluate urinary oxalate excretion associated with use of the supplements. Secondarily, to examine changes in fasting blood glucose (FBS), cholesterol and triglyceride levels with cinnamon and turmeric.
Study Design: Randomized crossover trial of 8 weeks' duration
Subjects: Healthy, non-diabetic subjects aged 21-38 years, mean BMI = 24.7 kg/m2 (data available for 7 women, 4 men).
Methods: With the exception of supplemental doses of cinnamon or turmeric, subjects were asked to maintain their normal dietary and exercise patterns for the entirety of the 8-week study period. Participants received 3.0 g cinnamon or 2.8 g turmeric in divided doses for 4 weeks, providing approximately 55 mg oxalate / day. Oxalate load tests were performed at study onset (with water only as a control) and at the end of each 4-week intervention period. The load tests required ingestion of a 63-mg oxalate load from the test agents (3.5 g cinnamon or 3.2 g turmeric). Fasting blood sugar (FBS) and lipid levels were also determined at these times. Subjects were given a detailed list of oxalate-rich foods and asked to avoid them starting the day before testing and for 24 hours post-oxalate ingestion. Subjects also fasted overnight for 12 hours prior to each collection day. They were instructed to arrive at the lab within 2 hours after their first urine voiding, then fasting blood tests were drawn, followed by collection of new urine samples (thereafter designated baseline urine samples). One of the oxalate-containing spices was then administered and urine samples were collected every 2 hours for 6 hours. Participants could then leave the lab, but were instructed to collect all urine to complete a 24-hour collection.
Results: Total oxalate content for cinnamon and turmeric was 1789 mg/100g and 1969 mg/100g, respectively. Turmeric had a markedly higher percentage of water-soluble oxalate than cinnamon (91% vs 6%), and ingestion of turmeric caused a higher level of urinary oxalate excretion during the oxalate load tests, especially during the initial 6 hours following oxalate ingestion. Twenty-four hour urine oxalate excretion increased from 19.9 mg (control) to 24.9 (turmeric). No significant changes in FBS or lipid profiles were found.
Conclusion: Consumption of supplemental turmeric, but not cinnamon, can significantly increase urinary oxalate levels, thereby increasing the risk of kidney stone formation in susceptible individuals.
Study strengths: Evaluations that took urine flow irregularities and missed collections into account.
Study weaknesses: Extremely small sample size; dosage employed for turmeric not explained; compliance assessed by pill count; assumption that endogenous oxalate synthesis occurs at a constant rate.
Of note: Oxalate is most commonly found in nuts, fruits and vegetables, grains and legumes; both soluble (sodium or potassium oxalate) and insoluble (calcium oxalate) forms are present in food; concomitant calcium ingestion reduces oxalate absorption, presumably by chelating oxalic acid in the small intestine; over 90% of absorbed oxalate can be recovered in the urine within 24-36 hours; there are no known gender differences with respect to oxalate absorption; mild side effects were noted with cinnamon (eructation, headache, burning sensation in stomach) but not with turmeric; standardized low oxalate and low calcium breakfast and snacks were provided the day of oxalate testing; 4 subjects had elevated triglyceride levels at baseline; cinnamon has a much higher calcium content than does turmeric, which likely contributes to its lower proportion of soluble oxalate as compared with turmeric; kidney stone formers may have an increased rate of endogenous oxalate synthesis, may absorb a higher percentage of dietary oxalate than non-stone formers, and may have high levels of oxalate intake; hypoglycemia was not experienced by any subject.
We knew that: Approximately 3/4 of all kidney stones are primarily comprised of calcium oxalate, and hyperoxaluria from both endogenous and exogenous sources is a primary risk factor for such stones; recent data suggest that even in the absence of gastrointestinal disease, intestinal absorption of oxalate makes a significant contribution to urinary oxalate levels, so that high oxalate intake becomes a risk factor for urolithiasis; prior human studies have suggested that supplemental doses of cinnamon can offer beneficial effects in the setting of diabetes and hyperlipidemia, with animal data suggesting the same for turmeric; hyperoxaluria has been defined as urine oxalate excretion that exceeds 40 mg/24 hours.
Comments: Cinnamon and turmeric have both become in recent years highly touted botanical agents, and for good reason. The results of sound research suggest potential benefits when these agents are added to conventional therapy for diabetes and dyslipidemia in the case of cinnamon, and as a chemo- and neuroprotective agent when the focus is on turmeric. Very little downside potential has been identified previously, and while the current trial is very small indeed as well as limited by assumption, its results do raise what appears to be a reasonable concern for people at risk of kidney stones. It seems prudent to advise people with a history of urolithiasis to proceed cautiously, if at all, with use of turmeric until further data come to light.
What to do with this article: Keep a hard copy in your file cabinet.
Greenfield, RH. Sweet Sleep –Cheese-Zit? Dairy and Acne. Alter Med Alert. 2008:11;94-95. Greenfield, RH. Curried Kidney Stones? Tumeric and Urolithiasis. Alter Med Alert. 2008:11;95-96.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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