Moderate soy intake improves survival in breast cancer patients

In a large prospective study of female breast cancer patients treated surgically, moderate soy intake was associated with a significant decrease in death and cancer recurrence during a 4 year follow-up.

A recent study published in the December 9, 2009 edition of the Journal of the American Medical Association provides more evidence of the safety of dietary soy intake in breast cancer patients.

Researchers found that a higher intake of soy foods was associated with a reduced risk of breast cancer recurrence as well as a lower risk of dying over a four year period following diagnosis.

Participants included 5,033 women in the Shanghai Breast Cancer Survival Study who were surgically treated for breast cancer. The women were enrolled between 2002 and 2006 and followed through June 2009. Intakes of soy protein and soy isoflavones were analyzed from several interviews and dietary questionnaires.

Over an average follow-up of about four years, women whose intake of soy protein was among the top 25 percent of participants had a 29 percent lower risk of death during follow-up and a 32 percent lower risk of recurrence compared to those whose intake was in the lowest quarter. When soy isoflavones were evaluated separately, the risk of dying over follow-up was 21 percent lower and the risk of recurrence was 23 percent lower for those whose intake was highest. The use of tamoxifen and hormone therapy were also associated with improved survival.

In this population-based prospective study, soy food intake was found to be safe and was associated with lower mortality and recurrence among breast cancer patients. The association of soy food intake with mortality and recurrence appears to have followed a linear dose response pattern until soy food intake reached 11 g/day of soy protein. No additional benefits on mortality and recurrence were observed with higher intakes of soy food. This study suggests that moderate soy food intake is safe and potentially beneficial for women with breast cancer.

Source: Soy Food Intake and Breast Cancer Survival, Shu et al, JAMA. 2009;302(22):2437-2443

Source: USANA Health Sciences

Fitness reduces the risk of death in men with metabolic syndrome

In a study of over 19,000 men, cardiorespiratory fitness significantly decreased risk of death compared to those who were unfit. Over the 17 years of the study, men with metabolic syndrome who were fit had half the death rate compared to men with metabolic syndrome who were not fit.

Metabolic syndrome is a cluster of disorders that include abdominal obesity, high blood pressure, elevated blood sugar, and unhealthy cholesterol levels. Up to one in four U.S. adults has metabolic syndrome, significantly increasing their risk for diabetes and cardiovascular disease.

In a study published in the Archives of Internal Medicine, over 19,000 men were recruited to determine the relationship between cardiorespiratory fitness (CRF) and mortality risk in healthy men and those with metabolic syndrome. The study group, which included 3,757 men with metabolic syndrome, were evaluated for fitness and then followed for up to 17 years.

Healthy men who were out of shape at the beginning of the study were three times as likely as their fit peers to die of cardiovascular disease. While men with metabolic syndrome were 89 percent more likely than healthy men to die of heart disease, men with metabolic syndrome who were unfit had twice the death rate as their fit counterparts.

According to the researchers, “This study strengthens the argument for aggressive public health campaigns aimed at increasing physical activity levels.” Fitness, regardless of body weight, can provide a strong protective effect against premature death in both healthy men and men with metabolic syndrome.

Source: Cardiorespiratory fitness attenuates the effects of the metabolic syndrome on all-cause and cardiovascular disease mortality in men, Katzmarzyk et al, Arch Intern Med 2004 May 24;164(10):1092-7.

Source: USANA Health Sciences

Insufficient vitamin D levels negatively affect strength in girls

Vitamin D deficiency can weaken the muscular and skeletal systems. New research has shown that higher vitamin D levels are positively related to strength and power in adolescent girls.

A paper published in the February 2009 edition of the Journal of Clinical Endocrinology and Metabolism reported a link between higher levels of vitamin D and greater strength in adolescent girls.

The participants were 99 girls between the ages of 12 and 14. None of the girls had symptoms of vitamin D deficiency, yet 70% had low blood levels of vitamin D (defined as less than 37.5 nmol/L).

Muscle power and force were analyzed through the use of jumping mechanography, which measures performance in a series of jumping activities. The girls who were low in vitamin D performed worse on the jumping tests compared with girls with higher vitamin D levels. Vitamin D levels were also positively correlated with jump velocity, jump height, muscle power, fitness, and force.

Even in the absence of visible symptoms of vitamin D deficiency, low levels of vitamin D affect the various ways muscles work and can affect overall strength and physical fitness.

Source: Vitamin D Status and Muscle Function in Post-Menarchal Adolescent Girls, Ward et al, J Clin Endocrinol Metab 2009 Feb;94(2):559-63.

Source: USANA Health Sciences

Probiotics help reduce upper respiratory tract infections in day care children

New research shows that Lactobacillus GG (LGG), a strain of probiotics, may decrease the risk of upper respiratory tract infections in children attending day care centers.

New research published in the Clinical Nutrition journal shows that Lactobacillus GG (LGG), a strain of probiotics, may decrease the risk of upper respiratory tract infections in children attending day care centers. The researchers also found that the rate of absence due to infection was lower in children receiving LGG when compared to placebo.

281 day-care attending children in Croatia were selected to participate in this randomized, double-blind, placebo-controlled trial. Over three months, the treatment group (139 children) received LGG in 100 mL of a fermented milk product. A matching placebo group (142 children) received the same fermented milk product, but without LGG. The children were not allowed to consume any other probiotic or prebiotic products during the study.

During the study, parents were contacted every 10 days and asked whether their child had developed any infections or side effects. Local doctors were responsible for the diagnosis and care of each child, and they were asked to record details of any infections the children experienced during the study period.

At the end of the three-month trial period, the authors found that children in the LGG group had a significantly reduced risk of upper respiratory tract infections when compared to placebo. However, they noted that there was no risk reduction in regard to lower respiratory tract infections as a result of the consumption of the LGG.

The researchers noted several limitations to their study, including the fact that diagnosis and treatment of the children was based only on the clinical judgment of local doctors. Additionally, the rate of severe infections was very low and, therefore, no clear effect of LGG could be proven. They also reported that since the study was conducted during the winter period (November to February), the season with highest risk of gastrointestinal infections (summer) was not included.

Nevertheless, as the paper’s conclusion states, “considering the significant decrease in the number of upper respiratory tract infections in children treated with LGG and knowing that the number needing treatment (NNT) was only five, we can recommend treatment with LGG as a valid measure for the prevention of upper respiratory tract infections in children who attend day care centres.”

Source: Hojsak I, Snovak N, Abdović S, Szajewska H, Mišak Z, Kolače S. Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centres: A randomized, double-blind, placebo-controlled trial, Hojsak et al, Clinical Nutrition Volume 29, Issue 3, June 2010, Pages 312-316

Source: USANA Health Sciences