Sunday, 24 April 2011

Controversies

There are a few popular idease that I am skeptical about. As an ex-scientist I'm well aware that data can be massaged to tell you exactly what you want to hear. However, when research that sounds controversial is published, it still makes for interesting reading and should be given due consideration.

There are many controversial issues around food. For example, the theory that artificial colours cause hyperactivity. In the April issue of Clinical Pediatrics, Dr Laura Stevens and co-workers reflect on 35 years of research looking for a causative link between artificial food colours and attention deficit hyperactivity disorder (ADHD).1 It has been shown that a small subgroup of children respond to artificial colours, when challenged with at least 100mg. [Note: Typically just 10 - 50 mg is used in a kg of food 2] The authors note that recently, 2 large studies demonstrated behavioral sensitivity to artificial food colourings and benzoate in children both with and without ADHD. However, the study does start off stating that artificial food colors have not been established as the main cause of attention-deficit hyperactivity disorder.

At the University of Osnabrück in Germany, Dr Bodo Melnik has suggested a relationship between milk and type 2 diabetes. 3 This is a proposed mechanism only and is based on the idea that drinking milk after weaning may cause signalling in the pancreas. This might overstimulate β-cell proliferation in the pancrease, and ultimately will speed up β-cell senescence. Both β-cell proliferation and sensecence are hallmarks of type 2 diabetes. The author also mentions a link with Alzheimer's Disease - this is because type 2 diabetes has been linked to an increased risk of Alzheimer's disease. 4 Of course, milk has also been shown to be an exceptional recovery drink for sportsmen, giving even better results than special sports drinks. 5,6

The latest sports-superfood is cherries. Researchers at London South Bank University have shown that Montmorency cherry juice consumption improves the recovery of isometric muscle strength after intensive exercise. 7 The researchers suggest that the cherries might have an anti-oxidative effect due to polyphenolic compounds including flavonoids and anthocyanins. [Interestingly, blueberries, chokeberries, European blackcurrants, elderberries and black raspberries contain significantly more flavonoids and anthocyanin than cherry 8]

On a non-food note, some researchers in China and the USA have published a case-control study investigating the link between breast cancer and sleeping with the light on.9 Subjects were identified in Connecticut, USA, and questioned with respect to their sleeping patterns and bedroom light environment. A non-significantly increased risk of breast cancer was observed among postmenopausal women for those keeping lights on while sleeping. This non-significant increased risk was also observed in women who reported mainly sleeping in the daytime and those not drawing the curtains while sleeping at night. The researchers conclude that this study suggest a potential increased risk of breast cancer associated with domestic exposure to light at night. Another group in Israel found a positive relation between breast cancer and light at night, and suggest that this may be due to disruption of the body's circadian clock.10 This correlation has not been found with lung cancer. 11





1 Stevens LJ, Kuczek T, Burgess JR, Hurt E, Arnold LE. (2000) Dietary Sensitivities and ADHD Symptoms: Thirty-five Years of Research. Clin Pediatr (Phila). 50: 279-93. Epub 2010 Dec 2.

2 http://www.understandingfoodadditives.org/pages/Ch2p1-3.htm

3 Melnik BC. (2011) Milk signalling in the pathogenesis of type 2 diabetes. Med Hypotheses. 76: 553-9. Epub 2011 Jan 19.

4http://www.nature.com/nrneurol/journal/v2/n3/full/ncpneuro0124.html

5 Pritchett K, Bishop P, Pritchett R, Green M, Katica C. (2009) Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance. Appl Physiol Nutr Metab. 34:1017-22.

6 Cockburn E, Stevenson E, Hayes PR, Robson-Ansley P, Howatson G. (2010) Effect of milk-based carbohydrate-protein supplement timing on the attenuation of exercise-induced muscle damage. Appl Physiol Nutr Metab. 35: 270-7.

7 Bowtell JL, Sumners DP, Dyer A, Fox P, Mileva KN. (2011) Montmorency Cherry Juice Reduces Muscle Damage Caused By Intensive Strength Exercise. Med Sci Sports Exerc. Jan 12. [Epub ahead of print]

8 http://www.mivelle.hu/sambucol/Flavonoid%20and%20Anthocyanin%20Content.pdf

9 Li Q, Zheng T, Holford TR, Boyle P, Zhang Y, Dai M. (2010) Light at night and breast cancer risk: results from a population-based case-control study in Connecticut, USA. Cancer Causes Control. 21: 2281-5. Epub 2010 Oct 7.

10 Kloog I, Portnov BA, Rennert HS, Haim A. (2011) Does the modern urbanized sleeping habitat pose a breast cancer risk? Chronobiol Int. 2: 76-80.

11 Kloog I, Haim A, Stevens RG, Barchana M, Portnov BA. (2008) Light at night co-distributes with incident breast but not lung cancer in the female population of Israel. Chronobiol Int. 25: 65-81.