Serum carotenoids and vitamins in relation to markers of endothelial function and inflammation.

Background: Endothelial cell dysfunction may be related to an increase in cellular oxidative stress. Carotenoids and vitamins could have an antioxidant-mediated tempering influence on endothelial function and inflammation, thereby reducing the risk of atherosclerosis.

Methods: We measured serum carotenoids, alpha-tocopherol and Vitamin C concentrations in 379 subjects sampled from the general population.

Dietary intervention in prostate cancer patients: PSA response in a randomized double-blind placebo-controlled study.

The objective of this study was to show or to exclude an effect of dietary supplement on rising prostate-specific antigen (PSA) levels. We have studied the effect of a dietary supplement (verum, administered for 6 weeks) containing plant estrogens, antioxidants, including carotenoids, selenium and other putative prostate cancer inhibiting substances in a randomized placebo-controlled double-blind crossover study in 37 hormonally untreated men with prostate cancer and increasing PSA levels. Outcome measures were changes in the rates of change of serum concentrations of total and free PSA and changes in male sex hormone levels.

Spread supplemented with moderate doses of vitamin E and carotenoids reduces lipid peroxidation in healthy, nonsmoking adults.

Background: High doses of vitamin E have been shown to decrease lipid peroxidation in persons under oxidative stress. At present, the data are insufficient to predict whether lower doses offer the same benefit in healthy persons.

Objective: We studied the effect of moderate doses of a combination of vitamin E and carotenoids, incorporated into a food product, on markers of antioxidant status and lipid peroxidation in healthy persons.

Determinants of skin sensitivity to solar irradiation.

Background: Acute effects of UV irradiation include UV-induced erythema. Sunlight plays an important role in the development of skin cancer. Several predictive factors of UV-induced erythema could also be predictive for skin cancer.

Decreased carotenoid concentrations due to dietary sucrose polyesters do not affect possible markers of disease risk in humans.

Excessive consumption of energy and fat increases the risk for obesity. Snacks containing sucrose polyesters (SPE) as a dietary fat replacer are on the market in the United States. SPE products have been shown to lower concentrations of serum carotenoids in short-term studies.

Olive oil phenolics protect LDL and spare vitamin E in the hamster.

An animal feeding trial was conducted to investigate whether olive oil phenolics can act as functional antioxidants in vivo. To this end, hamsters were exposed for a period of 5 wk to a dietary regime with either a phenol-rich extra virgin olive oil or extra virgin olive oil from which phenols were removed by ethanol/water-washing. The original oil used in the high olive phenol diet was also used for the preparation of the low phenol diet in order to keep the FA compositions exactly the same.

Macular pigment density in relation to serum and adipose tissue concentrations of lutein and serum concentrations of zeaxanthin.

Background: Macular pigment (MP), concentrated in the central area of the retina, contains the carotenoids lutein and zeaxanthin. A low MP density could be a risk factor for age-related macular degeneration. Little information is available regarding MP density in relation to serum lutein and zeaxanthin and adipose lutein concentrations in a general population.

Plasma concentrations of individual tea catechins after a single oral dose in humans.

1. Ten healthy volunteers ingested 1.5 mmole epicatechin gallate (ECg), epigallocatechin (EGC) or epigallocatechin gallate (EGCg) in a randomized crossover design.

Addition of milk does not affect the absorption of flavonols from tea in man.

Tea is a major source of flavonols, a subclass of antioxidant flavonoids present in plant foods which potentially are beneficial to human health. Milk added to tea, a frequent habit in the United Kingdom, could inhibit absorption of tea flavonoids, because proteins can bind flavonoids effectively. Eighteen healthy volunteers each consumed two out of four supplements during three days: black tea, black tea with milk, green tea and water.

Protection against nitric oxide toxicity by tea.

It is found that green tea and black tea are able to protect against nitric oxide (NO(*)) toxicity in several ways. Both green tea and black tea scavenge NO(*) and peroxynitrite, inhibit the excessive production of NO(*) by the inducible form of nitric oxide synthase (iNOS), and suppress the LPS-mediated induction of iNOS. The NO(*) scavenging activity of tea was less than that of red wine.

Effect of tea and other dietary factors on iron absorption.

Iron deficiency is a major world health problem, that is, to a great extent, caused by poor iron absorption from the diet. Several dietary factors can influence this absorption. Absorption enhancing factors are ascorbic acid and meat, fish and poultry; inhibiting factors are plant components in vegetables, tea and coffee (e.

Carotenoid bioavailability in humans from tomatoes processed in different ways determined from the carotenoid response in the triglyceride-rich lipoprotein fraction of plasma after a single consumption and in plasma after four days of consumption.

Tomatoes are the main dietary source of lycopene, and the bioavailability of lycopene from tomato paste is higher than that from fresh tomatoes. We investigated systematically the effect of mechanical homogenization and heating on the bioavailability of carotenoids from canned tomatoes. Further, we compared the carotenoid response in triglyceride-rich lipoproteins (TRL) after single consumption with the change in fasting plasma carotenoid concentrations after 4 d of daily consumption.

Amount of fat in the diet affects bioavailability of lutein esters but not of alpha-carotene, beta-carotene, and vitamin E in humans.

Background: Fat-soluble vitamin E and carotenoids are regarded as being protective against chronic diseases. Little is known about the effect of dietary fat on the bioavailability of these compounds.

Objective: The objective of this study was to assess the effect of the amount of dietary fat on plasma concentrations of vitamin E and carotenoids after supplementation with these compounds.

A single dose of tea with or without milk increases plasma antioxidant activity in humans.

Objective: To investigate the effect of black and green tea consumption, with and without milk, on the plasma antioxidant activity in humans.

Design: In a complete cross-over design, 21 healthy volunteers (10 male, 11 female) received a single dose of black tea, green tea (2 g tea solids in 300 ml water) or water with or without milk. Blood samples were obtained at baseline and at several time points up to 2 h post-tea drinking.

Influence of feeding different vegetables on plasma levels of carotenoids, folate and vitamin C. Effect of disruption of the vegetable matrix.

Carotenoids, folate and vitamin C may contribute to the observed beneficial effects of increased vegetable intake. Currently, knowledge on the bioavailability of these compounds from vegetables is limited. We compared the efficacy of different vegetables, at the same level of intake (i.

Effect of vegetable and carotenoid consumption on aberrant crypt multiplicity, a surrogate end-point marker for colorectal cancer in azoxymethane-induced rats.

Epidemiological studies indicate that increased vegetable consumption reduces the risk of colorectal cancer mortality. In the present study we have investigated the effect of consumption of standard diets supplemented with freeze-dried vegetables (peas, spinach, sprouts and broccoli) and carotenoids (all-trans beta-carotene and palm oil carotenoid extract) on surrogate end-point markers for colorectal cancer in an azoxymethane-induced rat model. Mean aberrant crypt multiplicity was reduced (19%) by the pea-supplemented diet only (P < 0.

Comparison of the bioavailability of natural palm oil carotenoids and synthetic beta-carotene in humans.

Palm oil carotenoids are a mixture of alpha- and beta-carotenes, which are used as food colorants. They may also be applied as a functional food ingredient because of the provitamin A activity of alpha- and beta-carotenes and their proposed beneficial roles in the prevention of chronic diseases. This paper discusses the results of an incomplete balanced crossover study with 69 healthy adult volunteers to compare palm oil carotenoids with synthetic beta-carotene in their efficacies to increase plasma levels of carotenoids.

Plasma and lipoprotein levels of tea catechins following repeated tea consumption.

Epidemiological studies suggest that antioxidant flavonoids in tea may reduce the risk of cardiovascular disease, possibly via protection of low-density lipoproteins (LDL) against oxidation. However, the extent of absorption of tea flavonoids and their accumulation in LDL during regular consumption of tea is not clear. Therefore we investigated plasma and lipoprotein levels of catechins during tea consumption and the impact on LDL oxidizability ex vivo.

Potential of vegetable processing to increase the delivery of carotenoids to man.

It has been suggested that carotenoids contribute to the inverse association between vegetable consumption and risk for coronary heart disease and cancer. However, there are indications that the bioavailability of beta-carotene from vegetables is less than previously thought. Therefore, it is of interest to explore whether the bioavailability of carotenoids from vegetables can be improved.

Bioavailability of catechins from tea: the effect of milk.

Objectives: To assess the blood concentration of catechins following green or black tea ingestion and the effect of addition of milk to black tea.

Design: Twelve volunteers received a single dose of green tea, black tea and black tea with milk in a randomized cross-over design with one-week intervals. Blood samples were drawn before and up to eight hours after tea consumption.

No effect of consumption of green and black tea on plasma lipid and antioxidant levels and on LDL oxidation in smokers.

Intake of flavonoids is associated with a reduced cardiovascular risk. Oxidation of LDL is a major step in atherogenesis, and antioxidants may protect LDL from oxidation. Because tea is an important source of flavonoids, which are strong antioxidants, we have assessed in a randomized, placebo-controlled study the effect of consumption of black and green tea and of intake of isolated green tea polyphenols on LDL oxidation ex vivo and on plasma levels of antioxidants and lipids.

Antioxidant fortified margarine increases the antioxidant status.

Objective: To assess the effect of supplementation with an antioxidant fortified margarine on the body's antioxidant status and on parameters of oxidative damage to lipids.

Design: Single blind, placebo controlled trial, two treatment groups balanced for sex, age and Quetelet Index.

Setting: Unilever Research Laboratorium, The Netherlands.

Effects of green tea, black tea and dietary lipophilic antioxidants on LDL oxidizability and atherosclerosis in hypercholesterolaemic rabbits.

The hypothesis that tea or dietary lipid-soluble antioxidants reduce atherogenesis by lowering the oxidizability of low-density lipoprotein (LDL) was investigated. Five groups of 20 female New Zealand white rabbits were fed a restricted amount of a high-fat (30 en%) semipurified diet supplemented with cholesterol (0.15%, w/w) for 21 weeks.