Gitte Ravn-Haren

Intake of whole apples or clear apple juice has contrasting effects on plasma lipids in healthy volunteers

PurposeFruit consumption is associated with a decreased risk of CVD in cohort studies and is therefore endorsed by health authorities as part of the ‘5 or more a day’ campaigns. A glass of fruit juice is generally counted as one serving. Fruit may cause protection by affecting common risk factors of CVD.MethodsApples are among the most commonly consumed fruits and were chosen for a comprehensive 5xa0×xa04xa0weeks dietary crossover study to assess the effects of whole apples (550xa0g/day), apple pomace (22xa0g/day), clear and cloudy apple juices (500xa0ml/day), or no supplement on lipoproteins and blood pressure in a group of 23 healthy volunteers.ResultsThe intervention significantly affected serum total and LDL-cholesterol. Trends towards a lower serum LDL-concentration were observed after whole apple (6.7xa0%), pomace (7.9xa0%) and cloudy juice (2.2xa0%) intake. On the other hand, LDL-cholesterol concentrations increased by 6.9xa0% with clear juice compared to whole apples and pomace. There was no effect on HDL-cholesterol, TAG, weight, waist-to-hip ratio, blood pressure, inflammation (hs-CRP), composition of the gut microbiota or markers of glucose metabolism (insulin, IGF1 and IGFBP3).ConclusionsApples are rich in polyphenols and pectin, two potentially bioactive constituents; however, these constituents segregate differently during processing into juice products and clear juice is free of pectin and other cell wall components. We conclude that the fibre component is necessary for the cholesterol-lowering effect of apples in healthy humans and that clear apple juice may not be a suitable surrogate for the whole fruit in nutritional recommendations.

Association between Polymorphisms in Glutathione Peroxidase and Selenoprotein P Genes, Glutathione Peroxidase Activity, HRT Use and Breast Cancer Risk

Breast cancer (BC) is one of the most common cancers in women. Evidence suggests that genetic variation in antioxidant enzymes could influence BC risk, but to date the relationship between selenoproteins and BC risk remains unclear. In this report, a study population including 975 Danish cases and 975 controls matched for age and hormone replacement therapy (HRT) use was genotyped for five functional single nucleotide polymorphisms (SNPs) in SEPP1, GPX1, GPX4 and the antioxidant enzyme SOD2 genes. The influence of genetic polymorphisms on breast cancer risk was assessed using conditional logistic regression. Additionally pre-diagnosis erythrocyte GPx (eGPx) activity was measured in a sub-group of the population. A 60% reduction in risk of developing overall BC and ductal BC was observed in women who were homozygous Thr carriers for SEPP1 rs3877899. Additionally, Leu carriers for GPX1 Pro198Leu polymorphism (rs1050450) were at ∼2 fold increased risk of developing a non-ductal BC. Pre-diagnosis eGPx activity was found to depend on genotype for rs713041 (GPX4), rs3877899 (SEPP1), and rs1050450 (GPX1) and on HRT use. Moreover, depending on genotype and HRT use, eGPx activity was significantly lower in women who developed BC later in life compared with controls. Furthermore, GPx1 protein levels increased in human breast adenocarcinoma MCF7 cells exposed to β-estradiol and sodium selenite.In conclusion, our data provide evidence that SNPs in SEPP1 and GPX1 modulate risk of BC and that eGPx activity is modified by SNPs in SEPP1, GPX4 and GPX1 and by estrogens. Our data thus suggest a role of selenoproteins in BC development.

Mini-review: The effects of apples on plasma cholesterol levels and cardiovascular risk - a review of the evidence

Summary Evidence suggests that a high intake of fruits is associated with a reduced risk of cardiovascular disease (CVD) and lowered plasma cholesterol, but the specific effects of individual types of fruit, fruit fractions, and processed fruit are less well-studied. Apples are among the most frequently consumed fruits, and human and animal studies on apple may help to clarify the effect of this fruit on CVD risk markers. The aim of this mini-review is to summarise current evidence for a lowering effect of apple on the risk of CVD and plasma cholesterol levels, and to investigate whether such an effect is influenced by fruit processing or the form of intake. Possible mechanisms behind the cholesterol-lowering effect of apples are also considered. All relevant published experimental studies in humans and animals were identified within the open literature. Nine human studies were identified, of which four concerned the effects of whole apples, two the effects of dried apples, and three the effects of filtered apple juice. Additional studies considered specific apple components. In general, there was a cholesterol-lowering effect, in the range of 5 – 8%, after the intake of approx. three whole apples, whereas the consumption of apple juice (375 – 720 ml) had no effect on plasma cholesterol levels and may result in adverse effects on plasma triglyceride levels. Limitations in the study designs did not allow us to draw conclusions on the effect of the intake of whole, dried apples (15 – 52 g). We also identified a total of nine experimental studies in animal models. Feeding with apple products resulted in decreased levels of plasma (11 – 43%) and liver (23 – 67%) cholesterol in the majority of studies. There was an increased excretion of bile acids (3 – 56%) and cholesterol (5 – 41%) in rats fed with apple products. Based on the current evidence from human observational and intervention studies, it seems likely that a reduction in plasma total and LDL cholesterol occurs after a dietary intake of apples, which could lead to a decreased risk of CVD. On average, a daily intake of approx. three apples resulted in a decrease in total cholesterol of 5 – 8% (approx. 0.5 mmol l−1). The consumption of filtered apple juice may result in adverse effects on plasma triglyceride levels. Evidence from animal studies suggests that the major mechanism behind the cholesterol-lowering effect of apples involves an increased clearance of plasma cholesterol due to enhanced faecal excretion of bile acids and cholesterol.