Experimental (Interventional) evidence carries the most weight
1. Meta-analysis of randomized clinical trials
2. Randomized, placebo controlled, double blind human trials
3. Open label (unblinded)
4. Animal studies
5. Petri dish studies
Observational (no attempt to affect outcome)
1. Mendelian randomization
1. Prospective cohort Study
2. Retrospective cohort study
3. Cross-sectional
4. Case control
Argumentative
1. Using animal or petri dish experiments, observational or testimonial data to infer a hypothesis
Testimonial
1. The experience of one person
The primary objective of health research is to determine what is likely to be true for the average individual. Statistically significant means a 95% chance that you will get the same result (p = .05) Highly statistically significant means a 99% change that you will get the same result (p = .01)
Correlation does not prove causation.
Lack of correlation does not prove lack of causation.
Correlations are considered more likely to be cause and effect if there is a plausible biological mechanism.
Saturday, November 6, 2010
There’s more than one way to be healthy.
There are 13 vitamins, 16 essential minerals, 9 essential amino acids, two essential fatty acids, many kinds of carbohydrates, many non essential nutrients including thousands of phytochemicals, over 20,000 genes and many lifestyle factors. The number of ways to shuffle the deck are almost infinite. It's not surprising that there are many different ways to survive and be reasonably healthy, some better than others.
1. Vegetarian Adventist men and women have expected ages at death of 87 and 89 years, respectively. They abstain from alcohol and tobacco, exercise regularly, eat nuts every day and eat more dairy products than average.
2. For Mormons, "Life expectancy from age 25 was 84 years for males and 86 years for females." They abstain from alcohol and tobacco, eat a lot of meat and don’t exercise more than typical Americans. They fast one day a month, which according to scientists seems to protect them from heart disease.
3. Japan has the best life expectancy of any country. The average man lives 79.4 years and the average women 86.1 years. They eat more carbs and less fat than the U.S. They have a high percentage of smokers. They eat more seafood than they do meat.
4. Iceland has the best longevity in Europe. The average man lives 80.1 years and the average women 83.5 years. They eat less carbs and more fat than the U.S. They eat more seafood than they do meat.
5. France has an extremely low rate of heart disease, but they have a high rate of cancer. They eat more saturated fat and less carbs than the U.S. They have a high percentage of smokers. They also tend to get a lot of vitamin K2 from cheese and goose liver, drink red wine with meals and ride bikes more than Americans which helps to reduce heart disease.
6. Rural China had an extremely low rate of heart disease as well as extremely low rates of prostate, breast and colon cancer. They also had extremely low total cholesterol (average of 127) but their rate of stroke is higher than the U.S. rate of heart disease. For the whole country, the average man lives 72.1 years and the average women 75.7 years. They have a high percentage of smokers. They don't eat much K2 or consume much alcohol. They ride bikes there even more than they do in France.
I don't believe it's a good idea for everyone to get total cholesterol under 160 because of an increased risk of stroke. On the other hand if you are treating heart disease that is a greater risk and going below 160 can be a life saving strategy. As long as you don't have hypertension, don't smoke or drink alcohol or caffeine, keep salt intake low, eat plenty of potassium rich foods and walk a lot there's probably little danger.
7. In the 1960s Crete had the best longevity in the world. They ate 40% fat mostly from olive oil, but only 8% saturated fat. The total red meat, poultry and fish consumed per-person, per-week in Crete was only about 371 grams (13 ounces).
8. For people who have trouble with unrefined carbs, there's the "Eco-Atkins", that's still lower in carbohydrates but contains much less animal fat and protein.
(In the US, the average man lives 75.7 years and the average women 80.7 years.)
1. Vegetarian Adventist men and women have expected ages at death of 87 and 89 years, respectively. They abstain from alcohol and tobacco, exercise regularly, eat nuts every day and eat more dairy products than average.
2. For Mormons, "Life expectancy from age 25 was 84 years for males and 86 years for females." They abstain from alcohol and tobacco, eat a lot of meat and don’t exercise more than typical Americans. They fast one day a month, which according to scientists seems to protect them from heart disease.
3. Japan has the best life expectancy of any country. The average man lives 79.4 years and the average women 86.1 years. They eat more carbs and less fat than the U.S. They have a high percentage of smokers. They eat more seafood than they do meat.
4. Iceland has the best longevity in Europe. The average man lives 80.1 years and the average women 83.5 years. They eat less carbs and more fat than the U.S. They eat more seafood than they do meat.
5. France has an extremely low rate of heart disease, but they have a high rate of cancer. They eat more saturated fat and less carbs than the U.S. They have a high percentage of smokers. They also tend to get a lot of vitamin K2 from cheese and goose liver, drink red wine with meals and ride bikes more than Americans which helps to reduce heart disease.
6. Rural China had an extremely low rate of heart disease as well as extremely low rates of prostate, breast and colon cancer. They also had extremely low total cholesterol (average of 127) but their rate of stroke is higher than the U.S. rate of heart disease. For the whole country, the average man lives 72.1 years and the average women 75.7 years. They have a high percentage of smokers. They don't eat much K2 or consume much alcohol. They ride bikes there even more than they do in France.
I don't believe it's a good idea for everyone to get total cholesterol under 160 because of an increased risk of stroke. On the other hand if you are treating heart disease that is a greater risk and going below 160 can be a life saving strategy. As long as you don't have hypertension, don't smoke or drink alcohol or caffeine, keep salt intake low, eat plenty of potassium rich foods and walk a lot there's probably little danger.
7. In the 1960s Crete had the best longevity in the world. They ate 40% fat mostly from olive oil, but only 8% saturated fat. The total red meat, poultry and fish consumed per-person, per-week in Crete was only about 371 grams (13 ounces).
8. For people who have trouble with unrefined carbs, there's the "Eco-Atkins", that's still lower in carbohydrates but contains much less animal fat and protein.
(In the US, the average man lives 75.7 years and the average women 80.7 years.)
What Okinawa centenarians eat
There's a myth that in Okinawa the people who live to be 100 are eating lots of pork and fat. The culture there is changing rapidly and many of the younger people do eat a lot of pork. But they trim the fat and boil the pork to remove even more fat. And teenagers are eating a lot of fast food. But if you want to know what the elders are eating, the Okinawa Centenarian Study has the answers.
Okinawan Elders
Meat/poultry/eggs - about 1 ounce per day
Fish - about 2 ounces per day
Dairy - very little
Grains - 32% of diet weight
Vegetables - 34% of diet by weight
Americans
Meat/poultry/eggs - About 10 times as much
Fish - a fraction of an ounce
Dairy - Over 10 times as much
Grains - About a third as much
Vegetables - About half as much
Based on page 71 of the Okinawa Program, a book written by the scientists involved in the study.
Okinawan Elders
Meat/poultry/eggs - about 1 ounce per day
Fish - about 2 ounces per day
Dairy - very little
Grains - 32% of diet weight
Vegetables - 34% of diet by weight
Americans
Meat/poultry/eggs - About 10 times as much
Fish - a fraction of an ounce
Dairy - Over 10 times as much
Grains - About a third as much
Vegetables - About half as much
Based on page 71 of the Okinawa Program, a book written by the scientists involved in the study.
Study: Atkins diet decreased blood flow to the heart
The effect of high-protein diets on coronary blood flow.
The Fleming Heart and Health Institute and the Camelot Foundation, Omaha, Nebraska 68114, USA. rfmd1@uswest.net
Abstract
Recent research has demonstrated that successful simultaneous treatment of multiple risk factors including cholesterol, triglycerides, homocysteine, lipoprotein (a) [Lp(a)], fibrinogen, antioxidants, endothelial dysfunction, inflammation, infection, and dietary factors can lead to the regression of coronary artery disease and the recovery of viable myocardium. However, preliminary work revealed that a number of individuals enrolled in the original study went on popular high-protein diets in an effort to lose weight. Despite increasing numbers of individuals following high-protein diets, little or no information is currently available regarding the effect of these diets on coronary artery disease and coronary blood flow. Twenty-six people were studied for 1 year by using myocardial perfusion imaging (MPI), echocardiography (ECHO), and serial blood work to evaluate the extent of changes in regional coronary blood flow, regional wall motion abnormalities, and several independent variables known to be important in the development and progression of coronary artery disease. Treatment was based on homocysteine, Lp (a), C-reactive protein (C-RP), triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and fibrinogen levels. Each variable was independently treated as previously reported. MPI and ECHO were performed at the beginning and end of the study for each individual. The 16 people (treatment group/TG) studied modified their dietary intake as instructed. Ten additional individuals elected a different dietary regimen consisting of a "high-protein" (high protein group/HPG) diet, which they believed would "improve" their overall health. Patients in the TG demonstrated a reduction in each of the independent variables studied with regression in both the extent and severity of coronary artery disease (CAD) as quantitatively measured by MPI. Recovery of viable myocardium was seen in 43.75% of myocardial segments in these patients, documented with both MPI and ECHO evaluations. Individuals in the HPG showed worsening of their independent variables. Most notably, fibrinogen, Lp (a), and C-RP increased by an average of 14%, 106%, and 61% respectively. Progression of the extent and severity of CAD was documented in each of the vascular territories with an overall cumulative progression of 39.7%. The differences between progression and extension of disease in the HPG and the regression of disease in the TG were statistically (p<0.001) significant. Patients following recommended treatment for each of the independent variables were able to regress both the extent and severity of their coronary artery disease (CAD), as well as improve their myocardial wall motion (function) while following the prescribed medical and dietary guidelines. However, individuals receiving the same medical treatment but following a high-protein diet showed a worsening of independent risk factors, in addition to progression of CAD. These results would suggest that high-protein diets may precipitate progression of CAI) through increases in lipid deposition and inflammatory and coagulation pathways.http://www.ncbi.nlm.nih.gov/pubmed/11108325
Study: Low carb/high meat diet increased cancer, heart disease & all cause mortality
Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies.
Harvard School of Public Health, Boston, Massachusetts 02115, USA. teresa.fung@simmons.edu
Comment in: Abstract
BACKGROUND: Data on the long-term association between low-carbohydrate diets and mortality are sparse.OBJECTIVE: To examine the association of low-carbohydrate diets with mortality during 26 years of follow-up in women and 20 years in men.
DESIGN: Prospective cohort study of women and men who were followed from 1980 (women) or 1986 (men) until 2006. Low-carbohydrate diets, either animal-based (emphasizing animal sources of fat and protein) or vegetable-based (emphasizing vegetable sources of fat and protein), were computed from several validated food-frequency questionnaires assessed during follow-up.
SETTING: Nurses' Health Study and Health Professionals' Follow-up Study.
PARTICIPANTS: 85 168 women (aged 34 to 59 years at baseline) and 44 548 men (aged 40 to 75 years at baseline) without heart disease, cancer, or diabetes.
MEASUREMENTS: Investigators documented 12 555 deaths (2458 cardiovascular-related and 5780 cancer-related) in women and 8678 deaths (2746 cardiovascular-related and 2960 cancer-related) in men.
RESULTS: The overall low-carbohydrate score was associated with a modest increase in overall mortality in a pooled analysis (hazard ratio [HR] comparing extreme deciles, 1.12 [95% CI, 1.01 to 1.24]; P for trend = 0.136). The animal low-carbohydrate score was associated with higher all-cause mortality (pooled HR comparing extreme deciles, 1.23 [CI, 1.11 to 1.37]; P for trend = 0.051), cardiovascular mortality (corresponding HR, 1.14 [CI, 1.01 to 1.29]; P for trend = 0.029), and cancer mortality (corresponding HR, 1.28 [CI, 1.02 to 1.60]; P for trend = 0.089). In contrast, a higher vegetable low-carbohydrate score was associated with lower all-cause mortality (HR, 0.80 [CI, 0.75 to 0.85]; P for trend </= 0.001) and cardiovascular mortality (HR, 0.77 [CI, 0.68 to 0.87]; P for trend < 0.001).
LIMITATIONS: Diet and lifestyle characteristics were assessed with some degree of error. Sensitivity analyses indicated that results were probably not substantively affected by residual confounding or an unmeasured confounder. Participants were not a representative sample of the U.S. population.
CONCLUSION: A low-carbohydrate diet based on animal sources was associated with higher all-cause mortality in both men and women, whereas a vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates.
PRIMARY FUNDING SOURCE: National Institutes of Health.
http://www.ncbi.nlm.nih.gov/pubmed/20820038
Protective Factors / Risk Factors
Protective factors:
- Calorie restriction is probably the most powerful way to reduce the rates of heart disease and cancer.
- Low glycemic index carbs.
- More omega-3 which is associated with lower rates of heart disease, lower triglycerides, longer telomeres and longer life.
- CLA which can be five times higher in grass fed meat inhibits the tumor promoting effects of IGF1. It's also helpful for heart disease.
- Physical exercise can reduce the rate of heart disease by 50%. It also reduces cancer rates.
- Vitamin K2 which is highest in goose liver, aged cheese and natto inhibits calcification of the arteries and is associated with lower rates of heart disease.
- A serving of wine or beer with a meal once or twice a day increases HDL. Alcohol with little or no food does not produce the same effect.
- Cabbage and onion family vegetables and tomatoes.
- Citrus and berries.
- Vitamin D3 (2000IU)
- Too much animal fat and protein.
- Too much sugar and white flour.
- Too much alcohol
- Too much salt
- Fried foods especially meat and potatoes.
- Sunburns and dark tans on light skinned people.
- Tobacco
- Obesity
- Diabetes
- Hypertension
Risk factors for cancer
Unadjusted cancer v. food item correlations comparing 50 countries that have very low or very cancer rates.
Apart from wine, the dangerous stuff is red meat, charcuterie and salt. A pavé de rum-steakmight not sound so mouth-watering after reading: "The risk of colon-rectal cancer rises by 29 per cent per 100-gramme portion of red meat per day and 21 per cent per 50-gramme portion of charcuterie."
http://www.timesonline.co.uk/tol/life_and_style/health/article5769159.ece
Cabbage family vegetables, onion family vegetables, and tomatoes have anti-cancer properties but it may be that most vegetables do not. If you drink moderately you'll probably live longer but you'll also probably die of cancer instead of something else.
Using data available at:
http://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html
The risk factors:
Alcohol
Tobacco
Sunburns
Over 10% of total calories from complete proteins especially meat
Fried foods especially potatoes
Vitamin D insufficiency
Sedentary lifestyle
Not enough cabbage and onion family vegetables and tomatoes
Not enough citrus and berries
- Alcohol r = .524 (p = .000)
- Potatoes r = .457 (p = .001)
- Animal fat r = .442 (p = .001)
- Meat r = .429 (p = .002)
- Vegetables (insignificant)
- Sugar (insignificant)
- Wheat (insignificant)
Plausible biological mechanisms
- Alcohol is a known Group1 carcinogen.
- Acrylamide from frying potatoes
- Heterocyclic amines from frying meat and increased IGF1 from consumption of complete proteins.
Apart from wine, the dangerous stuff is red meat, charcuterie and salt. A pavé de rum-steakmight not sound so mouth-watering after reading: "The risk of colon-rectal cancer rises by 29 per cent per 100-gramme portion of red meat per day and 21 per cent per 50-gramme portion of charcuterie."
http://www.timesonline.co.uk/tol/life_and_style/health/article5769159.ece
Studies do not support the hypothesis that glycemic load is associated with cancer, but high fructose consumption doesn't look good.
http://www.ncbi.nlm.nih.gov/pubmed/20711806
http://www.ncbi.nlm.nih.gov/pubmed/19336549
Controlled studies don't show that saturated fat promotes cancer.
http://www.ncbi.nlm.nih.gov/pubmed/19085838
Although trans fat is bad for heart disease it might actually be good for cancer.
http://www.ncbi.nlm.nih.gov/pubmed/17418560
http://www.ncbi.nlm.nih.gov/pubmed/19336549
Controlled studies don't show that saturated fat promotes cancer.
http://www.ncbi.nlm.nih.gov/pubmed/19085838
Although trans fat is bad for heart disease it might actually be good for cancer.
http://www.ncbi.nlm.nih.gov/pubmed/17418560
Cabbage family vegetables, onion family vegetables, and tomatoes have anti-cancer properties but it may be that most vegetables do not. If you drink moderately you'll probably live longer but you'll also probably die of cancer instead of something else.
Using data available at:
http://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html
http://faostat.fao.org/site/368/default.aspx#ancor
Association does not prove a cause and effect relationship and lack of association does not prove lack of a cause and effect relationship.
Association does not prove a cause and effect relationship and lack of association does not prove lack of a cause and effect relationship.
The risk factors:
Alcohol
Tobacco
Sunburns
Over 10% of total calories from complete proteins especially meat
Fried foods especially potatoes
Vitamin D insufficiency
Sedentary lifestyle
Not enough cabbage and onion family vegetables and tomatoes
Not enough citrus and berries
Low glycemic index carbs
Food Glycemic index
Fruits low
Non-starchy veggies low
All bran 30
Sprouted grain bread 36
Yams 37
Beans generally in the 40s
Multi grain bread 48
Spaghetti 48
Brown rice 50
Pumpernickel 51
Sweet corn 52
Sourdough 52
Rolled oats 55
Fruits low
Non-starchy veggies low
All bran 30
Sprouted grain bread 36
Yams 37
Beans generally in the 40s
Multi grain bread 48
Spaghetti 48
Brown rice 50
Pumpernickel 51
Sweet corn 52
Sourdough 52
Rolled oats 55
Monday, November 1, 2010
Diet and Telomeres
Cereal fiber associated with longer telomere length.
Linoleic acid associated with shorter telomere length.
http://www.ncbi.nlm.nih.gov/pubmed/20219960
Omega-3 associated with longer telomere length.
http://www.ncbi.nlm.nih.gov/pubmed/20085953
High meat consumption associated with coronary artery calcium
http://www.ncbi.nlm.nih.gov/pubmed/20723641
Processed meat associated with shorter teleomere length.
http://www.ncbi.nlm.nih.gov/pubmed/18996878
Ornish lifestyle changes associated with increased telomerase.
http://www.ncbi.nlm.nih.gov/pubmed/18799354
Curcumin (found in turmeric) inhibits telomerase. This might partly explain low life expectancy in India.
http://www.ncbi.nlm.nih.gov/pubmed/17569215
Exercise upregulates telomerase activity
http://circ.ahajournals.org/cgi/content/full/circulationaha;120/24/2405
Older people have shorter telomeres and cancer cells have shorter telomeres because of more cell divisions. Ninety percent of cancer cells express telomerase.
http://en.wikipedia.org/wiki/Telomere
Linoleic acid associated with shorter telomere length.
http://www.ncbi.nlm.nih.gov/pubmed/20219960
Omega-3 associated with longer telomere length.
http://www.ncbi.nlm.nih.gov/pubmed/20085953
High meat consumption associated with coronary artery calcium
http://www.ncbi.nlm.nih.gov/pubmed/20723641
Processed meat associated with shorter teleomere length.
http://www.ncbi.nlm.nih.gov/pubmed/18996878
Ornish lifestyle changes associated with increased telomerase.
http://www.ncbi.nlm.nih.gov/pubmed/18799354
Curcumin (found in turmeric) inhibits telomerase. This might partly explain low life expectancy in India.
http://www.ncbi.nlm.nih.gov/pubmed/17569215
Exercise upregulates telomerase activity
http://circ.ahajournals.org/cgi/content/full/circulationaha;120/24/2405
Older people have shorter telomeres and cancer cells have shorter telomeres because of more cell divisions. Ninety percent of cancer cells express telomerase.
http://en.wikipedia.org/wiki/Telomere
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