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Hydroxytyrosol is thought to be the main antioxidant compound in olive fruit, and it is believed to play a significant role in many of the health benefits attributed to olive oil. Previous research has linked the compound to cardiovascular benefits, typically reductions in LDL or “bad” cholesterol. Data has also suggested the compound may boost eye health and reduce the risk of macular degeneration.

Spanish researchers reported these results in the British Journal of Nutrition. Twenty-two healthy volunteers between 20 and 45 years of age and with a BMI between 18 and 33 kg/m2 were recruited. Volunteers were randomly assigned to receive 10 to 15 grams per day of hydroxytyrosol-enriched sunflower oil or non-enriched sunflower oil for three weeks. The former provided a daily hydroxytyrosol dose of between 45 and 50 mg. After the initial three week period, volunteers had two weeks of no intervention before crossing over to receive the other intervention.

Results showed no changes in total, LDL, or HDL-cholesterol between the groups. However, consumption of the hydroxytyrosol-enriched sunflower oil produced significant reductions in oxidized LDL from 79.8 units per liter at the start of the study to 64.1 U/l after three weeks, compared to an increase from 72.7 to 86.4 U/l during the control phase. Furthermore, the activity of arylesterase increased from 235.2 to 448.9 U/l during the hydroxytyrosol phase, compared with an increase from 204.1 to 310.3 U/l during the control phase.

The researchers reported that although hydroxytyrosol-enriched sunflower oil did not significantly reduce LDL-cholesterol or increase HDL-cholesterol, it acted as a functional food by increasing arylesterase activity and reducing oxidized LDL. Oxidized LDL is believed to be a major player in promoting atherosclerosis (the build-up of fatty plaques in arteries) and general cardiovascular disease. Based on these results, dietary sources of hydroxytyrosol appear to be capable of reducing certain risk factors associated with coronary artery disease.

Vazquez-Velasco M, et al. Effects of hydroxytyrosol-enriched sunflower oil consumption on CVD risk factors. 2010. Br J Nutr.

Age-Related Macular Degeneration (AMD) is the most common cause of vision loss in developed countries. This degenerative eye disease causes damage to the macula (central retina) of the eye, impairing central vision. People affected by AMD have difficulty reading, driving and performing activities that require clear central vision. Many factors contribute to the development of AMD, including aging, genetics, diet, and smoking. The macula is a yellow oval-shaped pigmented area located near the center of the retina. Structures within the macula are specialized to provide high-acuity vision. Lutein and zeaxanthin are found in high concentrations here, giving the macula its yellow color. This protective layer, known as macular pigment, filters harmful high-energy blue wavelengths of light preventing damage to the retina, cones, and rods.

Numerous published studies have previously reported a link to intakes of lutein and zeaxanthin and AMD risk; however, the research has been mostly inconsistent. In this newly published prospective study, researchers used two decades of data involving more than 100,000 participants from the Nurses’ Health Study and the Health Professionals Follow-up Study. All participants were aged 50 years or older and were free of diagnosed AMD, diabetes mellitus, cardiovascular disease, and cancer (except non-melanoma skin cancer) at baseline. The researcher’s analyzed carotenoid intake based on dietary food frequency questionnaires at baseline and follow-up, and then calculated predicted plasma carotenoid scores. The results of this study found that participants with the highest average plasma lutein and zeaxanthin levels had a 40% reduced risk of developing advanced AMD compared to those with the lowest average levels. “Lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilizing cell membranes,” the authors explain.

Dark green leafy vegetables are the primary dietary sources of lutein and zeaxanthin, but they are also found in some other colorful fruits and vegetables. Average dietary intake in the U.S. is only about 1-3 mg/day, far below the amount most studies indicate as a minimum needed to decrease risk of AMD. “Because other carotenoids may also have a protective role, a public health strategy of increasing the consumption of a wide variety of fruits and vegetables rich in carotenoids could be most beneficial and is compatible with current dietary guidelines,” the authors concluded.

JAMA Ophthalmol. 2015;133(12):1415-1424.

Osteo_SS_kneejointdamageOsteoarthritis (OA) is a degenerative joint disease that mainly affects cartilage, causing functional limitation and disability particularly in the elderly. It is estimated that over 27 million individuals over the age of 65 suffer from osteoarthritis, which most commonly affects the knee. Vitamin D plays many biological and functional roles in joint health, so vitamin D status may play a role in the progression of knee osteoarthritis.

In a new study published online in the Journal of Nutrition, researchers investigated whether serum vitamin D and parathyroid hormone (PTH) concentrations might predict the progression of knee OA. PTH is responsible for regulating the metabolism of vitamin D. The study included 418 participants enrolled in the Osteoarthritis Initiative who had at least one knee with diagnosed osteoarthritis. Serum vitamin D and PTH were measured at the 30 or 36 month visit of the study, and progression of OA was defined as an increase in the joint space narrowing (JSN) score between the 2 and 4 year study visits.

The average serum vitamin D level of the participants was 26 ng/ml, while 16% of this population had levels below 15 ng/ml. Between the beginning of the study and follow-up visits, 14% of the subjects experienced joint space narrowing (increased JSN score). Subjects with a low vitamin D level (< 15 ng/ml) had twice the risk of elevated knee OA progression than the participants with vitamin D levels > 15 ng/ml. Although a high serum PTH itself was not associated with a significant increase in JSN score, individuals with both low vitamin D and high PTH (> 73 pg/ml) had a greater than 3 fold increased risk of OA progression.

The results of the present study suggest that individuals deficient in vitamin D have greater risk of osteoarthritis progression than those with normal vitamin D levels.

Source:
Fang Fang Zhang et al. J Nutr. 2014; 144(12):2002-8. doi: 10.3945/jn.114.193227.

LemonPrevious observational studies have suggested that a higher intake of vitamin C is associated with a reduced risk of cardiovascular disease, primarily through effects on the endothelium (a thin layer of cells lining the interior of blood vessels). The endothelium has many important functions that include maintaining the flexibility of blood vessels and modulating the activity of certain white blood cells that are a significant part of the immune system.

In a recent meta-analysis published in the journal Atherosclerosis, researchers sought to determine the effect of vitamin C supplementation on endothelial function (EF) in adults, and whether the outcome differed by health status, study duration, dose and route of administration.

The study included 44 clinical trials and 1,129 adult participants. Supplemental vitamin C at oral doses of more than 500 mg was associated with significant improvement of endothelial function in subjects with cardio-metabolic disorders. The benefits of supplementation were primarily limited to people with atherosclerosis, diabetes, and heart failure. The study design, duration of supplementation, route of administration and baseline plasma vitamin C did not appear to significantly affect the outcome. There was a significant positive association between dosages greater than 500 mg/day and improvement in endothelial function.

The researchers noted that in addition to its effects on oxidative stress, vitamin C may positively affect nitric oxide, a potent vasodilator, reducing vascular inflammation. The results of this study indicate that vitamin C supplementation may improve endothelial function, especially in adults with a higher cardiovascular risk. Vitamin C supplementation, therefore, could potentially be a useful tool for the secondary prevention of cardiovascular diseases.

Source:
Ashor AW et al. Atherosclerosis.2014 Jul; 235(1):9-20.

An analysis of 70 trials reveals that omega-3 supplementation may be as effective at reducing blood pressure as other lifestyle intervention.

Nearly 4 out of 10 Australian adults have elevated blood pressure, which is linked to an increased risk of strokes, coronary heart disease, and total mortality.  A recent metaanalysis published in the American Journal of Hypertension analyzed 70 RCT trials to determine the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on blood pressure.

Weighted differences were used to separate individuals into an EPA+DHA group and a placebo group. All of the studies combined resulted in a 1.52 mm Hg reduction in systolic blood pressure and a 0.99 mm Hg reduction in diastolic blood pressure for the EPA+DHA group over the placebo group.

Additional data was used to further separate these into subgroups for additional analysis. This revealed even stronger effects of EPA+DHA, where a 4.51 mm Hg reduction in systolic blood pressure and a 3.05 mm Hg reduction in diastolic blood pressure were observed among untreated hypertensive subjects. In this subgroup, EPA+DHA treatment was as effective, or more effective, at lowering blood pressure than other lifestyle-intervention including increasing physical activity and restricting alcohol and sodium.

These results continue to build on prior evidence showing that omega-3 fatty acids may play a role in helping individuals control their blood pressure. One of the authors, Dominik Alexander, PhD, noted that “when measuring blood pressure, even small reductions can have a significant clinical impact.” A 2 mm Hg reduction in blood pressure reduces stroke mortality by 6%, coronary heart disease mortality by 4%, and total mortality by 3%.

Overall, available evidence from randomised controlled trials (RCT) indicates that provision of EPA+DHA reduces systolic blood pressure, while provision of ≥2 grams reduces diastolic blood pressure.

Source:
Miller, P.E. et al. Am J Hypertens. 2014 Mar 6. [Epub ahead of print] PMID:24610882

 

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LemonResults from a new meta-analysis indicate an association between improved survival among women with breast cancer who have a higher intake of vitamin C from supplements or food.

The association between dietary vitamin C intake and breast cancer survival is inconsistent and few studies have specifically examined vitamin C supplement use among women with breast cancer. In a new study published online in the European Journal of Cancer, Swedish researchers summarized results from prospective studies to determine whether there is an association between vitamin C intakes and the risk of breast cancer mortality.

The current meta-analysis identified ten studies that included 17,696 women who were diagnosed with breast cancer. The studies examined the effect of dietary vitamin C intake or supplementing with vitamin C following breast cancer diagnosis.

When the studies that reported the effects of vitamin C supplements were evaluated, their use was associated with a 19% lower risk of total mortality and a 15% lower risk of dying from breast cancer in comparison with no use. When analyzing vitamin C intake from foods, researchers observed that for every 100mg per day increase in dietary vitamin C there was 27% decrease in total mortality and 22% decrease in breast cancer-specific mortality.

Results from this meta-analysis indicate that vitamin C supplement use after breast cancer diagnosis is associated with a reduction in total mortality and breast cancer-specific mortality. More studies on post diagnosis supplementation should be conducted to confirm these results and further our understanding of how their use during radiation or chemotherapy may influence breast cancer outcomes.

Source:
Holly R. Harris et al (May 2014), European Journal of Cancer, Vol.50 (7):1223–1231

SunshineA new meta-analysis reveals that higher Vitamin D levels are associated with significantly reduced mortality in patients with colorectal and breast cancer.

Breast cancer (BC) and colorectal cancer (CRC) are two of the most common causes of cancer death worldwide. These cancers share many of the same risk factors which include smoking, physical inactivity, poor diet, excessive alcohol consumption and obesity. The results of several studies have suggested that low vitamin D levels may be a potential risk factor for many cancers, including BC and CRC.

In a recent study published in the European Journal of Cancer, researchers summarized the evidence regarding a potential protective role of high Vitamin D levels with cancer mortality, and specifically among breast cancer and colorectal cancer patients.

The comprehensive literature search included studies which analyzed the association of vitamin D with suvival in breast cancer and colorectal cancer patients. The review included five studies of colorectal cancer patients (n=2,330), and five studies of breast cancer patients (n=4,413). The studies all compared mortality across two to five categories of vitamin D levels.

Among colorectal cancer patients, when compared to the category of lowest vitamin D, the group with the highest vitamin D levels had a 29% decreased risk of overall cancer mortality, and a 35% decreased mortality risk of CRC specifically. Comparing high to low vitamin D levels among breast cancer patients revealed a 38% and 42% reduction of overall cancer and BC mortality respectively.

These results showed that higher Vitamin D levels (>75nmol/L or 30 ng/dl) were associated with significantly reduced mortality in patients with colorectal and breast cancer. Randomised controlled trials are needed to evaluate whether vitamin D supplementation can improve survival in colorectal and breast cancer patients with low vitamin D status (25(OH)D<50nmol/L) at diagnosis and before treatment

Source:
Maalmi H. et al. Eur J Cancer. 2014 Feb 27. pii: S0959-8049(14)00124-5.

salmonThe results of a new meta-analysis shows that long-term supplementation with omega-3s reduce blood markers of inflammation and may reduce the risk of chronic inflammatory-related diseases.

Inflammation is known to play a role in numerous chronic diseases such as diabetes, cardiovascular disease (CVD), obesity-related diseases, rheumatoid arthritis and other autoimmune diseases.  Omega-3 fatty acids have often been linked to providing benefits regarding these conditions, likely due to their anti-inflammatory function.

In a recent meta-analysis published in the online journal PLoS One, scientists reviewed the literature to determine the effect of marine-derived omega-3s on blood levels of several markers of inflammation.

The meta-analysis included 4,601 participants from 68 randomized, controlled trials of healthy subjects, subjects with chronic autoimmune diseases, and subjects with chronic non-autoimmune diseases (ie. cardiovascular disease). Fasting blood levels of the inflammatory markers TNF-a (tumor necrosis factor-alpha), IL-6 (interleukin-6) and CRP (C-reactive protein) were compiled and analyzed. Researchers also separated studies using omega-3s from supplementation as active treatment with those using omega-3s from dietary intake (fish) and included them into different meta-analyses.

A combined analysis of all study subjects revealed a significant link between omega-3 supplementation and decreased blood levels of CRP and IL-6. Among the subjects with chronic non-autoimmune disease, a longer duration of supplementation related to an even greater reduction in blood levels of IL-6 and TNF-a.  A similar finding was observed for IL-6 levels among healthy subjects. Higher dietary intake of omega-3s did result in lower IL-6 levels, but fish intake alone (without supplementation) did not appear to lower CRP or TNF-a.  The benefits of omega-3 supplementation were also more significant in non-obese subjects (BMI <30), particularly in the chronic non-autoimmune disease group.

The results of this study confirm that long-term supplementation of omega-3s from fish oil can effectively lower inflammatory markers and may help reduce the risk of chronic inflammation.

Source:
Li K, Huang et al.  PLoS ONE (2014); 9(2): e88103.

Avocado elerly-manA recent study published in the Journal of the American Medical Association (JAMA) reported on the benefits of vitamin E supplementation in mild to moderate Alzheimer’s disease. Researchers sought to determine if vitamin E, memantine (an ACE inhibitor), or both would slow progression of mild to moderate Alzheimer’s disease (AD).

The double-blind, placebo-controlled, randomized clinical trial involved 613 patients with mild to moderate Alzheimer (AD). Participants were randomized to receive 2,000 international units (IU) of vitamin E, or 20 milligrams of memantine, or a combination of both, or a placebo daily. The average follow-up was 2.3 years.

Patients were analyzed on their capability to perform daily living activities, memory and language, cognitive function, behavioral and psychological issues, and the time needing caregiver assistance. The data was measured and collected at the beginning of the study and every six months during the trial. Over the years of follow-up, scores declined by 3.15 units less in the Vitamin E group compared with the placebo group. In the memantine group, the scores declined 1.98 units less than the decline in the placebo group. Compared to the placebo group, those taking Vitamin E had an average delay in clinical progression of 19% per year, or approximately 6.2 months over the follow-up period.

Patients receiving the vitamin also needed less caregiver assistance in comparison with the placebo group. There was no significant difference in all-cause mortality or safety issues reported between the placebo and Vitamin E groups.

This study showed that high dose Vitamin E (2000 IU) appears to slow functional decline and decrease caregiver burden in patients with mild to moderate Alzheimer’s disease.

Source:
Maurice W. Dysken, MD et al. JAMA 2014; 311(1):33-44.

elerly-womanThere are numerous studies reporting the health benefits of increased fish consumption and higher intakes of the long-chain omega-3 polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

The National Heart Foundation of Australia recommends that, to lower the risk of cardiovascular disease, all adult Australians should consume 500 mg/day of combined EPA and DHA through 2–3 serves (150g serve) of oily fish per week and fish oil supplementation. For older adults, the risk of cardiovascular disease is higher; therefore, dietary strategies including increased intake of fish and omega-3 PUFA to reduce risk are necessary.

In the latest cross-sectional survey, 854 Australians (>= 51 yrs of age) were randomly selected to complete either an online survey or telephone interview. The survey included the quantitative fish frequency questionnaire and open- and closed-ended survey questions on demographics and supplement usage.

The survey found that on average:
•             The frequency of finfish/seafood consumption was 1.7 times per week (median intake 173 g);
•             13% never consumed finfish/seafood, or consumed less than once per month;
•             34% ate any type of finfish/seafood more than two times per week;
•             Only 28% consumed just 500 mg long-chain omega-3 PUFA per day from finfish/seafood alone;
•             The mean daily intake of long-chain omega-3 PUFA was 508 mg;

These data indicate that trends in fish intake in Australia are increasing. Although this is encouraging, the current survey still found that only 44% consumed finfish/seafood at least twice per week.  Among older Australians, the current fish consumption is low and many do not meet the current recommendations. Strategies to enhance intake to meet dietary recommendations in this older age group are required.

Source: Grieger, J A et al. Nutrition & Dietetics 2013; 70: 227–235

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