Team McCallum

R&D for Lifetime of Life

Pregnancy v autism.

A trio of researchers has discovered that if there is a short interval between first and second babies, the second one has an increased risk of autism.

The researchers looked at 660,000 pairs of siblings born in California between 1992 and 2002, where the first-born did not have autism. Then they compared the rates of autism in the second sibling, using the interval between when the mother first gave birth and when she became pregnant again.

Compared to an interval of 3+ years, an interval of 2-3 years resulted in an increase in the risk of autism by 27%, while 1-2 years increased the risk by 87% and under 1 year increased the risk by 139%.

The researchers checked their work using pairs of siblings where the 1st born had autism, and again found the second was at even greater risk if the interval was less than 3 years.

Experts in autism are cautioning that although the study appears sound, it is normal to wait for results to be replicated in a different group of people.

However, other studies have shown an increased risk of schizophrenia in the second born where there is a short interval between pregnancies. While other problems such as being severely pre-term are also linked to increased risk of autism.

Collectively, these suggest that a short interval increases the chance that the second child’s neural development is impacted.

The researchers speculated that the reason might be a depleted level of nutrients such as folate or iron, or elevated stress levels.

Until a mechanism is established, this would suggest mothers falling pregnant within 3 years of last giving birth should make sure their nutrients follow medical recommendations closely, and put practices in place to cut stress.


January 10, 2011 Posted by | Autism, Brain, Child Health, Diet, Minerals, Pregnancy, Stress, Success, Vitamins | Leave a comment

Calcium and vitamin D by IOM.

The Institute of Medicine (IOM) was asked by US and Canadian health authorities to conduct an independent, evidence based review of the dietary requirements for calcium and vitamin D.

Overall, the committee concludes that the majority of Americans and Canadians are receiving adequate amounts of both calcium and vitamin D. Further, there is emerging evidence that too much of these nutrients may be harmful.”

Prof A Catherine Ross chaired the committee conducting this update, the first since 1997. The team reviewed over 1,000 studies on vitamin D and calcium and took further evidence from experts.

The review covered all health outcomes,  including cancer, cardiovascular disease, high blood pressure, diabetes, metabolic syndrome, falls, immune response, neuropsychological functioning, physical performance, preeclampsia, and reproductive outcomes. It found that only in relation to bone health are the results unequivocal, and based its recommendations on this.

The committee noted that studies appearing in the media re population levels of deficiency are using arbitrary levels that have not been established by a central authority, and so have little validity.

Based on available data, the committee found almost all individuals get sufficient vitamin D when their blood levels are at or above 20 nanograms per milliliter as it is measured in the US, or 50 nanomoles per liter as measured in Canada.

Also, the committee considered that few people are getting their vitamin D from sunlight, and based their recommendations on this.

A full breakdown of the recommendations by age range and gender is at the IOM short report on calcium and vitamin D. Please note a number of special situations are omitted from this but are covered by the full 678 page report, so check with your physician.

Some subgroups—particularly those who are older and living in institutions or who have dark skin pigmentation—may be at increased risk for getting too little vitamin D.

National surveys in both the United States and Canada indicate that most people receive enough calcium, with the exception of girls ages 9-18, who often do not take in enough calcium. In contrast, postmenopausal women taking supplements may be getting too much calcium.

Too much calcium is linked with kidney stones, while too much vitamin D is linked to kidney and other tissue damage. The short report therefore gives 3 values for each group – the estimated average amount (enough for the average person), the recommended dietary allowance (the level at which nearly everyone gets enough) and the upper level intake (the level at which more will cause harm rather than good).

In conclusion, “the committee emphasizes that, with a few exceptions, all North Americans are receiving enough calcium and vitamin D. Higher levels have not been shown to confer greater benefits, and in fact, they have been linked to other health problems, challenging the concept that “more is better.””

November 30, 2010 Posted by | Aging, Calcium, Canada, Cancer, Child Health, Cognitive decline, CVD - cardiovascular disease, Diabetes, Gender, High blood pressure, IOM - Institute of Medcine, Metabolic syndrome, Success, United States, Vitamin D | Leave a comment

Supplements v weight gain.

Dr Lan-Juan Zhao studied the effect of calcium supplements and vitamin D supplements v weight gain in post-menopausal white women over a period of 4 years, with 870 completing the study.

The team concluded “Study results show beneficial effects of high calcium intake on obesity in a population-based study of postmenopausal women who have a relatively high baseline calcium intake. However, vitamin D supplementation may have no additional effect on body composition.”

One group of women took calcium plus vitamin D, another calcium plus placebo, while the controls took two placebos.

Overall, there was no clinically significant difference in body mass index changes for the 3 groups (although calcium plus vitamin D was slightly better than calcium only which edged ahead of none).

What was significant was that both calcium groups retained more lean tissue and lost more fat in the body trunk than the control group.

The team thought the fact that most of their drop-outs left in years 1 and 2 was not significant for the results. However, the calcium-only group shows a quick spike in weight gain in year 1, stable in year 2, and returning to base weight only during years 3 and 4.

In comparison, the calcium plus vitamin D group did not spike and showed a (very modest) reduction in BMI by the end.

The amounts taken were 1.4 grams/day of calcium and 1,100 IU of vitamin D3.

August 17, 2010 Posted by | Aging, BMI - body mass index, Bodyfat%, Calcium, Lan-Juan Zhao, Minerals, Obesity, Success, Vitamin D, Weight management | Leave a comment

Calcium supplements & heart attacks.

Dr Ian R Reid has reported on a meta-analysis study, in the British Medical Journal, that found that calcium supplements are associated with a 30% greater risk of heart attacks.

The team looked at 11 studies where calcium supplements were tested without vitamin D. These studies mainly investigated calcium supplements in osteoporosis treatment. None of the studies specifically investigated calcium supplements v heart attacks.

Dr Reid was interested because – calcium supplements give only a small benefit in osteoporosis treatment yet are widely used – dietary calcium appears to protect the cardiovascular system – yet calcium supplements appear to make the cardiovascular system worse – according to other studies.

So he pooled results from 11 studies covering nearly 12,000 people, looking only at those where vitamin D was not used, as vitamin D has been shown to have a protective effect on the heart.

Dr Reid and colleagues concluded “Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.”

July 30, 2010 Posted by | CVD - cardiovascular disease, Diet, Health, High blood pressure, Ian R Reid, Minerals, Osteoporosis, Success, Vitamin D | 1 Comment