CLA, Vitamin D, Omega-3 & B6
Research Bulletin - 27th July 2007 Safety of Clarinol Conjugated
Linoleic Acid (CLA). The research, published in the current issue of
the International Journal of Obesity, supports the safety behind the Clarinol
ingredient that has been questioned by some contradictory results. CLA is
a fatty acid naturally present in meat and dairy products. The food industry often
removes fat from dairy products to produce low fat versions that will be acceptable
to consumers causing CLA to be removed along with it. This has drastically reduced
CLA intake in the Western population. The subjects in this study were overweight
and obese men and women (average age 47.3, BMI 28-32 kg per sq.m), and were assigned
them to receive daily CLA supplements (3.4 grams per day) or placebo (olive oil)
for six months. A subset of 49 subjects agreed to participate in an euglycemic
hyperinsulinemic clamp study - considered the gold standard for measuring insulin
resistance. Forty-one subjects completed this test. This study helps alleviate
fears that using CLA on a long term basis may have adverse effects. In conclusion,
CLA can be used safely for weight management along with a calorie controlled diet
and a healthy lifestyle. International Journal of Obesity Volume
31, Pages 1148-1154 Vitamin B6 use during Pregnancy If the
results, published in the American Journal of Epidemiology, are repeated in more
studies in other populations around the world, it may see vitamin B6 force an
extension of the current "Big 3" of pregnancy nutrition: folic acid, calcium with
vitamin D, and omega-3 fatty acids. The researchers, from U of M Amherst,
University of Illinois, Harvard Medical School, Anhui Medical University (China),
Northwestern University, and Children's Memorial Hospital and Children's Memorial
Research Center, looked at the B vitamin status (folate, B6 and B12) of 364 women
(average age 24.9, average BMI 19.8 kg per sq. m) working in the textile industry
in Anqing, China. The women were included if they conceived at least once
during prospective observation (1996-1998) and provided daily urine samples over
a 12-month period. The urine was tested for human chorionic gonadatropin (hCG)
to detect conception and early pregnancy loss. Ronnenberg and co-workers
report that women with vitamin B6 levels above 38.3 nanomoles per litre increased
the odds of conception by 120 per cent, and halved the odds for early pregnancy
loss if levels were above 46.4 nanomoles per litre. They also report that
sufficient levels of B6, defined as levels above 30 nanomoles per litre, improved
the odds of conception by 40 per cent and lowered the odds for early pregnancy
loss by 30 per cent, compared to women with B6 deficiency. This study supports
the use of food supplements during pregnancy as this is a period in which the
mother's demands for extra nutritents may not be supplied by diet alone. American
Journal of Epidemiology, Volume 166, Number 3, Pages 304-312 Omega-3
fatty acids from fish may protect against colorectal cancer. The epidemiological
study, published in the American Journal of Epidemiology, adds to a growing body
of science linking omega-3 and fatty fish consumption to a reduced risk of colorectal
cancer, although more research is necessary, particularly randomised controlled
trials. The researchers, from the University of Edinburgh, University of
Aberdeen, and Edinburgh's Western General Hospital, recruited 1,455 subjects with
colorectal cancer (cases), and 1,455 matched healthy controls. Although
trans-monounsaturated fatty acids and palmitic, stearic, and oleic acids were
dose-dependently associated with colorectal cancer risk, these links were no longer
observed after adjusting the results for potential confounding factors. Consumption
of omega-3 polyunsaturated fatty acids was associated with a 37 per cent reduction
of colorectal cancer risk, comparing highest against lowest average intakes. Increased
intake of EPA was associated with a 41 per cent reduction in risk, while DHA was
associated with a 37 per cent reduction in risk, comparing highest against lowest
average intakes. It has previously been proposed that omega-3 fatty acids
may inhibit the omega-6 arachidonic acid (AA) cascade that has been linked to
cancer formation and cell proliferation. American Journal of Epidemiology,
Volume 166, Issue 2, Pages 181-195 Vitamin D deficiency linked to metabolic
syndrome. The research, published online in the journal Clinical Nutrition,
adds to an ever-growing body of science linking vitamin D deficiency to increased
risk of certain diseases, including certain cancers, type-2 diabetes and osteoporosis. It is not clear from the study however if supplementation with the vitamin
could prevent the development of metabolic syndrome among obese patients and more
research is necessary to explore the potential benefits of the vitamin for at-risk
populations. Botella-Carretero and co-workers recruited 73 morbidly obese
patients (BMI 40 kg per sq. m) and diagnosed 37 with vitamin D deficiency. Forty-six
of the patients also had MetS. Over 60 per cent of those with MetS were
vitamin D deficient, compared to only 33 per cent of those without the syndrome. It was also observed that blood levels of HDL-cholesterol were lower (37.
mg/dl vs. 44.9 mg/dl), and triglycerides levels were higher (163.3 mg/dl vs. 95.1
mg/dl) in the vitamin D-deficient group compared to the vitamin S-sufficient group. The
researchers stated that vitamin D deficiency has previously been linked to impaired
insulin secretion in animals and humans, and has also been linked to insulin resistance
in healthy, glucose-tolerant subjects. However, Botella-Carretero and co-workers
said that these links could be confirmed by their study. Clinical Nutrition
(Elsevier) Published on-line ahead of print, J.I. Botella-Carretero et al. Vitamin
D and calcium supplements may aid the healing of bone fractures.. The
combination of vitamin D and calcium has long been recommended to reduce the risk
of bone fracture for older people, particularly those at risk of or suffering
from osteoporosis, which is estimated to affect about 75m people in Europe, USA
and Japan. The researchers looked at the effect of joint vitamin D, calcium
supplementation on elderly subjects with history of fractures due to osteoporosis.
The researchers note that such a population are marked by poor bone status, vitamin
D deficiency, and low physical performance, and are susceptible to low-energy
fractures of the hip, forearm, shoulder, and spine. In a double-blinded
design, 122 patients (average age 70) with hip fracture (lower-extremity fracture,
or LEF) or upper extremity fracture (UEF) were randomly assigned to receive 3000
mg calcium carbonate plus1400 IU cholocalciferol, or placebo (200 IU cholecalciferol)
for one year. Sixty-eight per cent of participants (79 subjects) completed the
study. The regimens were taken in combination with a multivitamin tablet (Pharma
Vinci A/S, Denmark). Hitz and co-workers report that vitamin D status, measured
using concentrations of 25-hydroxyvitamin D2, increased as a result of supplementation
but not placebo, with the greatest improvements observed in the hip fracture patients.
The group say vitamin D levels increase from 33 to 82 nmol/L. Bone turnover
also decreased as a result of intervention, measured using parathyroid hormone
(PTH) levels, although bone resorption (weakening of the bone) remained high in
hip fracture patients who received the intervention, with the researchers suggesting
this could be due their low mobility. Source: American Journal of Clinical
Nutrition 2007, Volume 86, Pages 251-259 |
