Publications by authors named "Harryvan J"

Background: Large genome-wide association (GWA) studies of European ancestry individuals have identified multiple genetic variants influencing iron status. Studies on the generalizability of these associations to African ancestry populations have been limited. These studies are important given interethnic differences in iron status and the disproportionate burden of iron deficiency among African ancestry populations.

View Article and Find Full Text PDF

Purpose: Dietary intake of B vitamins and methionine, essential components of DNA synthesis and methylation pathways, may influence colorectal tumor (CRT) development. The impact of B vitamins on colorectal carcinogenesis in individuals with Lynch syndrome (LS) is unknown but is important given their high lifetime risk of developing neoplasms. The role of MTHFR C677T genotype in modifying these relationships in LS individuals is also unclear.

View Article and Find Full Text PDF

Background: Colorectal adenomatous polyposis is associated with a high risk of colorectal cancer (CRC) and is frequently caused by germline mutations in APC or MUTYH. However, in about 20-30% of patients no underlying gene defect can be identified. In this study, we tested if recently identified CRC risk variants play a role in patients with >10 adenomas.

View Article and Find Full Text PDF

Thymidylate synthase and serine hydroxymethyltransferase are involved in folate metabolism. In a case-control study, including 768 cases and 709 controls, we investigated the associations between colorectal adenomas and TS tandem repeat and SHMT1 C1420T polymorphisms, and the interplay with B-vitamins. The polymorphisms were not associated with adenomas, but there was a borderline significant interaction between TS genotype and vitamin B6: the association between vitamin B6 and adenomas seemed positive in TS 3R/3R individuals, but inverse in TS 2R/2R individuals.

View Article and Find Full Text PDF

We investigated the associations between dietary intake of folate and vitamin B2, MTHFR C677T genotype, and colorectal adenomas in a Dutch case-control study. Data of cases with at least one histologically confirmed colorectal adenoma (n = 768) and controls with no history of any type of colorectal polyp (n = 709) were included. Dietary intake was assessed using a food-frequency questionnaire.

View Article and Find Full Text PDF

Objectives: The content of n-3 (omega-3) polyunsaturated fatty acids in fat tissue is a valid indicator of their long-term consumption. We studied the stability of n-3 fatty acids in human subcutaneous fat microbiopsies after 6 and 11 y of storage.

Design: Microbiopsies were taken from a lump of human adipose tissue and stored at +20 and -80 degrees C.

View Article and Find Full Text PDF

Background: Nondigestible oligosaccharides have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and by decreasing the toxicity of the colon contents.

Objective: We compared the effect of 2 doses of transgalactooligosaccharides and a placebo on the composition and activity of the intestinal microflora in 18 women and 22 men.

Design: Strictly controlled experimental diets were supplied to 3 intervention groups in a parallel design.

View Article and Find Full Text PDF

Intake of dietary flavonols and flavones was inversely associated with risk for cardiovascular disease in several epidemiologic studies. This may have been due to effects on hemostasis because flavonoids have been reported to inhibit platelet aggregation in vitro. We indeed found that 2500 micromol/L of the flavonol quercetin and the flavone apigenin significantly inhibited collagen- and ADP-induced aggregation in platelet-rich plasma and washed platelets by approximately 80-97%.

View Article and Find Full Text PDF

The fatty acid composition of serum cholesteryl esters is used as a qualitative biomarker of fatty acid intake, but quantitative data are scarce. Between 1987 and 1992, the authors fed various fatty acids in four controlled trials to 232 healthy Dutch volunteers and measured the proportion of fatty acids in participants' cholesteryl esters. Each 10% of energy fed as linoleic acid (18:2) raised the proportion of linoleic acid in cholesteryl esters by 9.

View Article and Find Full Text PDF

The content of n-3 (omega 3) polyunsaturated fatty acids in fat tissue is an indicator of their long-term consumption. Therefore, a method for determining n-3 fatty acids in human fat tissue microbiopsies was validated and the stability of n-3 fatty acids in biopsies was checked under various conditions of storage. Methyl esters were prepared from 25 to 35 mg adipose tissue and separated by capillary gas chromatography.

View Article and Find Full Text PDF

Scandinavian-style boiled coffee, which raises serum cholesterol, was found to contain more lipid material than drip filter coffee, which does not. Ten volunteers consumed a lipid-enriched fraction from boiled coffee for six weeks: the supplement provided 77 g of water, 1.3 g of lipid, and 1.

View Article and Find Full Text PDF