In Chapters 1 and 2, we examined two key components of heathy dietary patterns, specific types of dietary fat and consumption of fruit and vegetables, in relation to total and cause-specific mortality in two prospective cohort studies, the Nurses’ Health Study and the Health Professionals Follow-up Study. Dietary intake was assessed using semi-quantitative food frequency questionnaires at baseline and updated every 2 to 4 years. In Chapter 1, we found that higher saturated and trans fat intakes were associated with higher mortality, whereas polyunsaturated and monounsaturated fat intakes were inversely associated with mortality. Replacing 5% of energy from saturated fats with equivalent energy from polyunsaturated fats and monounsaturated fats was associated with 27% and 13% estimated reductions in total mortality, respectively. Intake of n-6 polyunsaturated fat, especially linoleic acid, was inversely associated with mortality, while marine n-3 polyunsaturated fat intake was associated with a modestly lower total mortality. In Chapter 2, we observed an inverse and nonlinear association between fruit and vegetable consumption and mortality. Consumption of five servings of fruit and vegetables daily, two servings for total fruit and three servings for total vegetables, were associated with the lowest total mortality, but above that level, higher consumptions were not associated with additional risk reductions. Higher consumptions of most fruit and vegetable subgroups were associated with lower risks of total mortality, whereas higher intakes of starchy vegetables such as peas and corn were associated with slightly higher risk of total mortality. In Chapter 3, we investigated the interrelationships between plasma ceramide concentrations, Mediterranean dietary pattern and cardiovascular disease (CVD) in the PREDIMED trial, a randomized controlled trial on the Mediterranean diet for primary prevention of CVD, using a case-cohort design. We observed strong positive associations between plasma ceramide concentrations and CVD risk. The association between ceramide concentration and incident CVD significantly varied by intervention groups. A Mediterranean diet may mitigate the deleterious effects of elevated plasma ceramide concentration.
In summary, our findings from the three studies support current dietary recommendations to replace saturated and trans fat with unsaturated fats, increase fruit and vegetable consumption and adopt healthy Mediterranean-style dietary patterns.
| Identifer | oai:union.ndltd.org:harvard.edu/oai:dash.harvard.edu:1/27201720 |
| Date | 01 May 2017 |
| Creators | Wang, Dong |
| Contributors | Hu, Frank B. |
| Publisher | Harvard University |
| Source Sets | Harvard University |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation, text |
| Format | application/pdf |
| Rights | open |
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