Stable Isotopes In Nutritional Studies

Stable isotopes are very useful tools which are used extensively in scientific research. Within the field of nutritional studies stable isotopes are used for studying the flow of nutrients through the human body. Since they are safe and non-radioactive they can even be used in infants and pregnant women.

Compounds containing stable isotopes can be identified and measured using the molecular weight of the compound. This is because it will differ from that of the original compound. Using an instrument called a mass spectrometer, researchers can use this weight difference to trace the stable isotopes as they travel through the body and appear in blood, urine, breath, and stool samples.

The first paper published that described the use of a stable isotope tracer in a human metabolic study was in 1963. Today, there are four commonly studied isotopes used in nutrition studies, which include calcium, iron, magnesium and zinc.

Calcium Isotopes are used at length in clinical research studies. Calcium has six stable isotopes, which include ⁴⁰Ca, ⁴²Ca, ⁴³Ca, ⁴⁴Ca, ⁴⁶Ca and ⁴⁸Ca. They are used to measure calcium absorption mainly in women and children. In adults, calcium deficiency is strongly related to increasing severity of osteoporosis. In children, calcium deficiency is primarily related to the development of rickets. (S.A. Abrams and W.W. Wong, Stable Isotopes in Human Nutrition, 2003).

There are four stable Iron Isotopes: ⁵⁴Fe, ⁵⁶Fe, ⁵⁷Fe and ⁵⁸Fe. The two most commonly used isotopes in nutritional studies are ⁵⁷Fe and ⁵⁸Fe. One study, conducted by the University of Iowa and the University of Texas (Samuel J. Fomon et al., January 2003) involved the use of ⁵⁸Fe to study iron-loss by human adolescents. The investigators were able to estimate inevitable iron loss by adolescents because total body iron of the adolescents had been enriched with the stable isotope, ⁵⁸Fe, as the result of earlier studies of iron absorption. At the conclusion of this study, they were able to estimate the requirement for absorbed iron.

The consequences of magnesium deficiency are more difficult to identify which can be associated with the difficulties of conducting stable magnesium isotope studies. There are only two stable Magnesium Isotopes: ²⁵Mg and ²⁶Mg are regularly used in studies. It is known that magnesium is important in bone and muscle function. Deficiency conditions have been associated with disorders including bone loss, diabetes and neurological impairment (Rude, 1998).

There are five stable Zinc Isotopes: ⁶⁴Zn, ⁶⁶Zn, ⁶⁷Zn, ⁶⁸Zn and ⁷⁰Zn. The three most commonly used isotopes in nutritional studies are ⁶⁷Zn, ⁶⁸Zn and ⁷⁰Zn. There are many studies being conducted in areas including the deficiency of zinc in children in developing countries and absorption rates of zinc. A deficiency of zinc can cause poor growth, reduced

resistance to infections, and life-threatening bouts of diarrhea and pneumonia. More
information can be found at the USDA/ARS Children's Nutrition Research Center at
Baylor College of Medicine.

      Trace Sciences can provide all of the above isotopes mentioned. We are the only
         supplier who can supply high-enriched ⁴³Ca and ⁴⁸Ca for nutritional studies. We
            also supply a full range of isotopes for other fields of scientific research. Please
               contact us for more information and refer to our Enriched Stable Isotopes
                  page for a complete overview of our products.