Marja‐Leena Ovaskainen

Conjugated linoleic acid (CLA) is anticarcinogenic in experimental animal studies. We studied dietary and serum CLA in Finnish patients with breast cancer in 1992-1995. Participants were consecutive women with breast cancer (68 premenopausal and 127 postmenopausal) and population-based control women (75 premenopausal and 133 postmenopausal), matched for age and area of residence. Diet was assessed by a validated food frequency questionnaire and the fatty acid composition of serum by gas-liquid chromatography. In postmenopausal women, dietary CLA, serum CLA, myristic acid, and trans-vaccenic acid were significantly lower in cases than in controls. The odds ratio for breast cancer in the highest quintile vs. the lowest was 0.4 [95% confidence interval (CI) = 0.2-0.9]for CLA, 0.3 (95% CI = 0.1-0.7) for myristic acid, and 0.3 (95% CI = 0.1-0.7) for trans-vaccenic acid in serum. The odds ratios remained similar after adjustment for known risk factors of breast cancer. A diet composed of CLA-rich foods, particularly cheese, may protect against breast cancer in postmenopausal women, but it is impossible to assess the independent effects of CLA in this study. The findings may be of relevance for food production, inasmuch as it is possible to increase CLA and its precursor trans-vaccenic acid in foods by modifying the feeding of ruminants.

Subjects with higher preference for evening hours in daily activities (eveningness) have been repeatedly shown to practice adverse health behaviors as compared to those preferring morning hours (morningness). However, associations between chronotype and dietary intake have not been explored intensively. The authors explored whether the human chronotype is associated with food and nutrient intakes in a random sample of the population aged 25 to 74 yrs. The cross-sectional study included 4493 subjects from the National FINRISK 2007 Study. Chronotype was assessed using a shortened version of Horne and Östberg's Morningness-Eveningness Questionnaire. Diet was assessed using a validated food frequency questionnaire. Associations between morningness-eveningness (ME) score and dietary intakes were analyzed by linear regression and difference between lowest (eveningness) and highest (morningness) ME score quintiles by Tukey's test. In the multivariable model, intakes of whole grain, rye, potatoes, and vegetables and roots decreased, whereas those of wine and chocolate increased with lower ME scores. Participants in the lowest ME score quintile consumed less fish (p < .001) and fruits (p = .025) and more chocolate (p = .001) and soft drinks (p = .015) compared to the highest quintile. No linear association was found between ME score and total energy intake. In regression analyses, intake of alcohol (as a percentage of total energy intake; E%) and sucrose (E%) increased, whereas intake of carbohydrates (E%), protein (E%), fiber, folic acid, and sodium decreased with lower ME scores. Furthermore, participants in the lowest ME score quintile ingested more fat (E%) (p < .001) and less vitamin D (p < .001) compared to the highest quintile, even though no linear trend between ME score and these nutrients emerged. In conclusion, these results support existing evidence that individuals with circadian preference toward eveningness have less healthy lifestyles, such as unfavorable dietary habits, than those with tendency toward morningness, which could put them at higher risk of several chronic diseases.