Dienstag, 27. November 2012

Cliffnotes on vegetarianism: Yes, you should eat less meat and more veggies.

Ever since I read the 1999 meta-analysis of vegetarian diets and mortality (2) I wanted to see a follow-up. Finally, some epidemiologists gave it another try.

Enter Huang et al. 2012 (1):
Seven studies with a total of 124,706 participants were included in this analysis. All-cause mortality in vegetarians was 9% lower than in nonvegetarians (RR = 0.91; 95% CI, 0.66-1.16). The mortality from ischemic heart disease was significantly lower in vegetarians than in nonvegetarians (RR = 0.71; 95% CI, 0.56-0.87). We observed a 16% lower mortality from circulatory diseases (RR = 0.84; 95% CI, 0.54-1.14) and a 12% lower mortality from cerebrovascular disease (RR = 0.88; 95% CI, 0.70-1.06) in vegetarians compared with nonvegetarians. Vegetarians had a significantly lower cancer incidence than nonvegetarians (RR = 0.82; 95% CI, 0.67-0.97).”
"Begg’s funnel plot and Begg’s test showed a slight significant publication bias in all-cause mortality, cancer incidence, ischemic heart disease and circulatory disease. No publication bias was observed in cerebrovascular disease."
Nonetheless the risk ratio for cerebrovascular disease is not materially different from the other risk estimates, arguing against the null hypothesis. What this may suggest is inadequate statistical power.
And there was some heterogeneity between studies
and residual confounding or bias always remain a big problem in observational studies of this sort. However, sensitivity analysis showed that heterogeneity did not unduly influence the data. 

If it were not for supportive evidence from other study designs, including well designed controlled trials, I wouldn't consider this study to be all that solid evidence. But we do have evidence that:
  • dietary patterns like "prudent", Mediterranean, vegetarian + (marine) n-3
  • food groups like legumes, vegetables, fruit, nuts, olive and n-3 rich plant oils, whole-grains
  • dietary substances abundant in plant foods like fibre, potassium, magnesium, vitamin K, antioxidants, plant protein, secondary plant metabolites, etc. are healthy
and that plants lack many detrimental substances found in foods of animal origin like heme iron, saturated fat, cholesterol, toxic compounds formed due to cooking and heat, BCAA & methionine rich protein.

NB: the above is a simplification and much more could be said on the topic. There is evidence that a vegetarian diet can be further optimized by including low fat dairy and either a source of marine n3 fatty acids or regular intakes of ALA (=n3 of plant origin).. that lowish intakes of white meat can be acceptable... that vegetarian diets can be improved by supplementation and much more.

(1) Ann Nutr Metab. 2012;60(4):233-40. doi: 10.1159/000337301. Epub 2012 Jun 1.
Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review.
Huang T, Yang B, Zheng J, Li G, Wahlqvist ML, Li D.

(2) Am J Clin Nutr. 1999 Sep;70(3 Suppl):516S-524S.
Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Key et al.

Samstag, 17. November 2012

Barack Obama defended the presidency and why the heck should I care?

I refuse to believe that politics must be about ideology. Most politics and policy deals with reality and as such ought to be evidence-based. As it happens, there is usually a party that sides with reality more closely. So why was this election critical?

There are good reasons why the US election is an international issue most importantly globalisation, but we also should emphasize with the American people. Of course, Barack Obama is not a good president, far from it, but the only realistic alternative was cataclysmic.Therefore the election can be considered a small win for science over noise, which was perfectly predicted in advance by the famous poll aggregator Nate Silver.

To understand why, let's look at science and health policy: With the Republican slash and burn approach to the budget, funding for the National Institute of health (NIH) and National Institute of Aging (NIA) would be in jeopardy. We already know funding for the NIH wasn't exactly rosy during the last Republican administration.
However, research may be crippled by other means too. Remember that it was the Republican George W. Bush who appointed and listened to bioethicists like Leon Kass, who is not only anti-abortion and anti-stem cell research, but also firmly opposed to life extension. With such monstrous friends who needs enemies? I doubt a republican president would be less radical today, given the strong grip the Tea Party has on the GOP.
And this is not offset by any benefits to the free market, i.e. pharma companies, that I know of.
Tens of thousands die due to a lack of insurance each year, and it took a Democrat to broaden coverage against fierce opposition. Colour me unimpressed, Republicans.
On the other hand, if a Supreme Court of the United States (SCOTUS) appointee leads to an overturn of Roe v. Wade, allowing bans on abortion, tens, probably hundreds, of thousands will die as an (in)direct consequence of medical complications and of being born into dysfunctional families.

A SCOTUS and president that kills Roe v. Wade may enable the teaching of creationism in school, even if it is just by a back-door.
The Republicans continue to deny the scientific fact of AGW and ecological problems, and under such an administration reckless exploitation of the environment will continue to erode the long-term growth potential of the US.

Republican economic policy paints a picture just as bleak:
While Obama generally embraces very successful new Keynesian economics, that saved (or could have saved) millions of jobs. His opponents call for pernicious tax cuts for the rich, severe spending cuts in a depressed economy, undermine Social Security, continued deregulation, etc., showing their disdain for the poor.

The republican war mongers brought us two unnecessary wars that cost trillions, which could have been spent on - oh, I don't know - education,  research, biogerontology and the global fight against poverty. Foreign policy is one of the key the reasons why Republican politicians are despised in most developed countries.

The Republican track record on social issues is even more horrifying: jingoism, homophobia, racism, misogyny ("the war on women"), prudery and radical evangelical Christianity are rampant in their party from the bottom rungs to the top - with few exceptions.

Disaster has been averted, for now.

Mittwoch, 7. November 2012

What can you do to help us slow, prevent or reverse aging?

You can donate…

Donate to the SENS foundation, or the MFoundation. Or longecity.com aka imminst, if you like grassroots efforts.

…or do something else
  • Spread the word: blog, tweet, post, like it, talk about it.
  • Critize it! A good scientist will always change his or her opinion given new evidence. Discuss and provide constructive criticism.
  • Do the science, or support the science. Get a degree and support your local university.
  • Buy a book or two. You can learn more about the topic of healthy life extension. Ending Aging is a good start, or another book on biogerontology (no particular recommendation yet)
  • Get political and petition your government. Contact local politicians. Vote accordingly.
  • Indirectly, promote a world view that values: humanism, atheism and agnosticism, critical thinking, equality, LGBT and women’s rights, a healthy diet, the fight against poverty, science, education, freedom and smart growth, environmentalism, liberal and progressive social democracy and the free distribution of knowledge.
  • Look out for yourself: eat a healthy mostly plant based, low or moderate calorie diet. Work out, don't stress, don't smoke etc. However, never forget that only biomedical research will lead to true advances.

There’s much more, other Ideas from...

... Longecity

... Dr. Aubrey de Grey's SENS.org

...The MFoundation

this post was adapted from the above sources.

Sonntag, 4. November 2012

The Magic of Buying in Bulk

I know this is obvious to some, but I just realised this and it bears stressing: buying in bulk has considerable advantages. This is an easily overlooked benefit of having a stable diet.

Buying in bulk is:
  • practical and efficient, you can save a lot of time at the store.
  • possibly healthier, because storage condition can be optimised, which is particularly important for fatty foods. Especially those containing easily damageable polyunsaturated fatty acids. Retailers often do a terrible job with storage. Nuts and olive oil (EVOO) should be stored cool (8-10°C) and not be exposed to light, for instance, but I have never seen a store do this.
  • ecological, because you need less packaging material.
  • cheaper, since you get discounts.