Two cohort studies examined the effects of low-carbohydrate diets on mortality, revealing that higher animal-based low-carbohydrate diets were linked to increased all-cause and specific mortality, while vegetable-based low-carbohydrate diets were associated with decreased mortality. The findings suggest that the type of protein and fat in low-carbohydrate diets significantly influences health outcomes, with vegetable sources being preferable. Overall, the studies indicate a nuanced relationship between carbohydrate intake and health, emphasizing the importance of dietary composition.

1. www.pronutritionist.net
Low-Carbohydrate Diets and All-
Cause and Cause-Specific
Mortality
Two Cohort Studies
Fung T et al.
Ann Intern Med 2010;153:289-298
Page 1 Fung T et al. Ann Intern Med 2010;153:289-298

2. Page 2
Background
• Several studies have demonstrated that a low-
carbohydrate diet is at least as effective as a calorie-
restricted, high-carbohydrate, low-fat diet for weight
loss
• However, effects on blood lipid profiles for low-
carbohydrate diets are mixed
– low-carbohydrate diets resulting in greater improvements in
high-density lipoprotein cholesterol and triglyserides
– but less favorable changes in low-density lipoprotein
cholesterol levels than higher carbohydrate diets
• Different types of low carb diets may impact health
differently
• Long-term data on low-carbohydrate diets and
mortality are insufficient (Yancy et al. 2010)
Fung T et al. Ann Intern Med 2010;153:289-298 www.pronutritionist.net

3. Methods (1/2)
• Two prospective cohort studies
• n = 85 168 women from Nurses’ Health Study
• aged 34 to 59 years at baseline
• follow-up 26 years
• n = 44 548 men from Health Professionals’ Follow-up Study
• aged 40 to 75 years at baseline
• follow-up 20 years
• food intake was followed with food-frequency questionnaires
Page 3 Fung T et al. Ann Intern Med 2010;153:289-298 www.pronutritionist.net

4. Methods (2/2)
• low-carbohydrate scores was calculated to
characterize low-carbohydrate diets on the basis of the
1. proportion of carbohydrate, fat, and protein in the diet
2. the contribution to these macronutrients from animal or
vegetable sources
• scores:
– overall low-carbohydrate score
– animal low-carbohydrate score
– vegetable low-carbohydrate score
www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-2984

5. Results
• Both men and women who had higher overall and animal low-
carbohydrate scores had
– higher BMI
– were more likely to be current smokers
– had lower intakes of fruits and vegetables
• those with higher vegetable low-carbohydrate score tended to
have higher alcohol and whole grain intake
• In the extreme low decile of carbohydrate intake, daily intake was
152 g for women and 166 g for men
• In extreme high decile of carbohydrate intake, daily intake was
275 g for women and 305 g for men
Page 5 Fung T et al. Ann Intern Med 2010;153:289-298 www.pronutritionist.net

6. Results
• overall low-carbohydrate diet score was only weakly
associated with all-cause mortality (HR 1,12)
• a higher animal low-carbohydrate diet score was
associated with
– higher all-cause mortality in men and women
– cancer and cardiovascular mortality in men
• a higher vegetable low-carbohydrate score was
associated with lower mortality and particularly CVD
mortality
• When cancers were broken into subclasses, it was
found that colorectal and lung cancers were more
common in low carb animal based group (Appendix
material) than in high carb animal based group
www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-2986

7. Hazard ratio comparing low carbohydrate intake to
high intake: all-cause mortality (pooled)
www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-2987
*p < 0.001

8. www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-2988
Multivariate-adjusted hazard ratio comparing
extreme deciles: cardiovascular mortality (pooled)
p < 0.001
P =0,029

9. Multivariate-adjusted hazard ratio comparing
extreme deciles: cancer mortality (pooled)
www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-2989
None of the pooled comparisons is statistically significant. However, in separate
analyses both in women and men the differences in animal based became significant
P =0,089
P =0,23

10. Discussion (1/2)
• Classification of carbohydrate diets in the study does not
match with current thinking of low carbohydrate diet. In the
lowest decile of intake, participants still had carbohydrate
intake of c. 150-170 grams per day
• “A low-carbohydrate diet” based on animal sources was
associated with modestly higher (12 %) all-cause mortality
in both men and women
• Vegetable-based “low-carbohydrate diet” was associated
with 15 % lower all-cause and 21 % lower cardiovascular
disease mortality vs respective high carbohydrate diets
Page 10 Fung T et al. Ann Intern Med 2010;153:289-298 www.pronutritionist.net

11. Discussion (2/2)
• Results suggest that the health effects of a low-
carbohydrate diet may depend on the type of protein and
fat, and a diet that includes mostly vegetable sources of
protein and fat is preferable to a diet with mostly animal
sources of protein and fat
• The study results are in line with another large cohort
study from US ( Halton et al. 2006 ), and with European
cohort studies (Lagiou et al 2007 and Trichopoulou et al.
2007 )
www.pronutritionist.netFung T et al. Ann Intern Med 2010;153:289-29811