Saturday, June 09, 2007


Rather to my surprise, I can't see much wrong with the study immediately below. Nice to see some double-blind evidence instead of epidemiological garbage. What was shown is that rubbing vitamin A cream into yourself puffs up your skin and so reduces wrinkles

Improvement of Naturally Aged Skin With Vitamin A (Retinol)

By Reza Kafi et al.

Objective: To evaluate the effectiveness of topical retinol (vitamin A) in improving the clinical signs of naturally aged skin.

Design: Randomized, double-blind, vehicle-controlled, left and right arm comparison study.

Setting: Academic referral center.

Patients: The study population comprised 36 elderly subjects (mean age, 87 years), residing in 2 senior citizen facilities.

Intervention: Topical 0.4% retinol lotion or its vehicle was applied at each visit by study personnel to either the right or the left arm, up to 3 times a week for 24 weeks.

Main Outcome Measures: Clinical assessment using a semiquantitative scale (0, none; 9, most severe) and biochemical measurements from skin biopsy specimens obtained from treated areas.

Results: After 24 weeks, an intent-to-treat analysis using the last-observation-carried-forward method revealed that there were significant differences between retinol-treated and vehicle-treated skin for changes in fine wrinkling scores (-1.64 [95% CI, -2.06 to -1.22] vs -0.08 [95% CI, -0.17 to 0.01]; P<.001). As measured in a subgroup, retinol treatment significantly increased glycosaminoglycan expression (P = .02 [n = 6]) and procollagen I immunostaining (P = .049 [n = 4]) compared with vehicle.

Conclusions: Topical retinol improves fine wrinkles associated with natural aging. Significant induction of glycosaminoglycan, which is known to retain substantial water, and increased collagen production are most likely responsible for wrinkle effacement. With greater skin matrix synthesis, retinol-treated aged skin is more likely to withstand skin injury and ulcer formation along with improved appearance.

Arch Dermatol. 2007;143:606-612


There is a whole industry telling us how good for us Brussels sprouts are -- which is entirely predictable from the fact that they taste bad. So after the sound study above we need a laugh, so let us have a look at some epidemiology about sprouts.

The big hole in epidemiological studies is that you can never be certain what caused an observed difference. Just suggest a reasonable alternative causal chain to that advanced in the original study and the original study proves nothing. So I will just suggest my old favourite -- the one that most medical researchers zealously ignore -- the role of social class.

The basic question that the study raises is: Why would healthier people say they eat more sprouts? My guess is because economically more successful people are better at saying the "right" things. So the study has really only separated out the dummies from the smarties -- and it is an old and general truth that dumber and poorer people have worse health. This study is another instance of it. It proves nothing about actually eating sprouts!

The abstract is pretty heavy going even after I have paragraphed it so I start below with a media summary and then give the abstract:

BRUSSEL sprouts may not be a dinner-party favourite, but they could protect you against bladder cancer. In the International Journal of Cancer this week, researchers report that so-called "cruciferous" vegetables, such as brussel sprouts, broccoli, cauliflower, turnips, cabbage, radish and watercress help to prevent cancer because they are rich in chemicals called isothiocyanates (ITCs). The study included 697 patients who had recently been diagnosed with bladder cancer and 708 healthy controls. Participants completed a dietary survey to assess their intake of ITCs. Bladder cancer patients had a significantly lower daily intake of ITCs than the cancer-free controls. Overall, high ITC intake was associated with a 29 per cent lower risk of bladder cancer. This anti-cancer effect was stronger in men, in patients aged 64 or older, and in smokers.


Dietary isothiocyanates, GSTM1, GSTT1, NAT2 polymorphisms and bladder cancer risk

By Hua Zhao et al.

Isothiocyanates (ITCs) are nonnutrient compounds in cruciferous vegetables with anticarcinogenic properties. ITCs down-regulate cytochrome P-450 biotransformation enzyme levels, activate Phase II detoxifying enzymes and induce apoptosis. On the other hand, ITCs also serve as a substrate for GSTs. Experimental evidences suggest that ITCs have anticarcinogenic effect on bladder cancer. Therefore, we evaluated dietary intake of ITCs, GSTM1, GSTT1 and NAT2 polymorphisms, and bladder cancer risk in a case-control study.

There were 697 newly diagnosed bladder cancer cases identified from The University of Texas M. D. Anderson Cancer Center and 708 healthy controls matched to cases by age (~5), gender and ethnicity. Participants underwent an in-person interview, in which epidemiologic and food frequency questionnaires were administered to collect demographic and dietary intake data.

Median ITC intake per day was statistically significantly lower in cases than in controls (0.23 vs. 0.33, p < 0.001). High ITC intake was associated with 29% decreased risk of bladder cancer [Odds ratio (OR) = 0.71, 95% confidence interval (CI) = 0.57, 0.89]. The protective effect was more evident in older individuals ( 64-years-old), men, ever smokers and heavy smokers in stratified analysis. Compared with NAT2 rapid acetylator, NAT2 slow acetylator had an increased risk of bladder cancer in Caucasians (OR = 1.31, 95% CI = 1.02, 1.69). There was no main effect associated with the GSTM1 or GSTT1 genotypes. The protective effect of ITCs against bladder cancer was not modified by GSTM1, GSTT1 or NAT2 genotypes. This is the first epidemiological report that ITCs from cruciferous vegetable consumption protect against bladder cancer.


Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].

Trans fats:

For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.


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