October 2012

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Research update: Soapy’ taste of coriander linked to our genes

There are some who love that unique coriander fragrance being released on the chopping board, while others are repulsed by it, claiming it has a soap-like smell. Both groups seem to never fi nd common ground, but now new research is shedding light on why, so reports the journal Nature1. A genetic comparison was made of two samples of nearly 30,000 participants; the fi rst sample included participants of European ancestry who reported whether coriander tasted ‘soapy’ and the second was a replication population that included a distinct set of participants who had declared their like or dislike of coriander. The researchers identifi ed two genetic variants linked to perception of coriander, suggesting that our genes may be at least partly responsible for our mixed reactions to this fragrant green herb. The strongest-linked variant was found to lie within a cluster of olfactory-receptor genes, which are associated with our sense of smell. One of these genes is OR6A2; this gene encodes a receptor that detects aldehyde compounds, which give coriander its soapy smell.

The researchers conclude that OR6A2 is “a compelling candidate gene for the detection of the coriander odours that give coriander its divisive fl avour”. However, the researchers also calculated that less than 10 per cent of coriander preferenceis due to common genetic variants – this might suggest that coriander preference involves multiple genes, as many other complex traits do, or that the heritability of coriander preference is just rather low.

‘how to’... beat the autumnal blues

As nights draw in and the days become colder and darker, it is not uncommon to feel a bit down.

Here are six tips to help you adjust to the seasonal changes:

By far the most important factor is exercise. This doesn’t have to be at a gym. In fact, research into ‘green exercise’ (exercising outdoors) in clinical populations with a range mental health problems has consistently shown significant improvements in mood and self-esteem. And there’s something special about wrapping up in your new winter running gear, and going out for a brisk walk in the woods with friends or family, then coming home to a nice hearty meal.

Natural daylight will help balance your circadian rhythm – the day-night cycle to which our hormonal and neurological systems have evolved to respond. Try and go outdoors during your lunch break or consider purchasing or hiring a lightbox. Protein in the diet is important in maintaining good mood. Aim for 1g per kg of body weight. Increase your intake of vitamin D, the so-called “sunshine vitamin”. The best way to top up your vitamin D is by getting natural sunlight, although the British weather can make this diffi cult. You may also want to supplement your diet with 2000 IU vitamin D during the darker winter months.

Omega-3 fatty acids from oily fi sh have been shown to have positive effects on our mood. Opt for fi sh such as mackerel, sardines, herring, anchovies, salmon, trout and pilchards. As nights draw in and the days become colder and darker, it is not uncommon to feel a bit down. Here are six tips to help you adjust to the seasonal changes: ‘how to’... beat the autumnal blues The supplement 5-HTP is the precursor to the neurotransmitter serotonin and has been shown to improve mood. Start by taking 50mg with water immediately before bed on an empty stomach. You can gradually increase the dose, up to 300mg, over a period of three weeks. Note: if you are on medication, do consult your GP fi rst before taking supplements.

Steaming destroys beneficial effects of onions

Onions form an important ingredient in many dishes around the world and are associated with a several health benefi ts. One such benefi t that has been attributed to onions and their constituents is their ability to inhibit platelet aggregation, which plays a key role in the development of atherosclerosis. However, a study recently published in Nutrition Journal2 now suggests that cooking onions may destroy their antiplatelet potential. In this study, onion quarters were steamed for 0, 1, 3, 6, 10 and 15 minutes and then juiced.

The in vitro antiplatelet activity of the onion juice was examined using the blood of 12 subjects. Results showed that raw juice signifi cantly inhibited the collagen-induced platelet aggregation response, while steaming for three to six minutes destroyed this antiplatelet activity. At 10 and 15 minutes steaming, the researchers observed not only a complete loss of antiplatelet activity, but also a stimulatory effect on platelet aggregation. Although the authors acknowledge that this was an in vitro study, the same effects may also occur in vivo, given the correct amount/type of cooked onion ingested and absorbed. They therefore suggest that consumers may want to minimize onion cooking time, choose onions with a high pungency for cooking, or consume raw onions on a regular basis, in order to preserve onion-induced antiplatelet activity.

Choline intake during pregnancy linked to lifelong health of children 

We all know what a vital role good nutrition plays during pregnancy. Expectant mothers are routinely advised to get at least 400mcg of folate a day, to prevent neural tube defects, such as spina bifi da, in their babies. Now, new research has highlighted another nutrient that is important in pregnancy and whose effects could last throughout the life of the unborn child3.

Consuming adequate amounts of choline, a nutrient usually grouped with the B-vitamins, during pregnancy may lower an infant's vulnerability to mental health problems and chronic conditions, such as high blood pressure, later in life. The new study found that higher amounts of choline in the diet during pregnancy changed “epigenetic markers” in the baby’s DNA, which determine whether specifi c genes are switched on or off. The markers affected were those regulating the hypothalamicpituitary-adrenal or HPA axis, which controls virtually all hormone activity in the body. The researchers also found that doubling the amount of choline mothers ingested, from 480mg to 930mg a day, led to a one-third reduction in levels of the stress hormone cortisol in the blood of their babies. Past research has shown that early exposure to high levels of cortisol can increase the lifelong risk of stress-related and metabolic disorders.

What’s up?

Don’t forget to come and see us at camexpo – the UK’s only dedicated professional holistic event. Camexpo will celebrate its tenth anniversary on 20-21 October at London’s Earls Court, with 200 leading exhibitors, over 100 seminars, workshops and demos hosted by some of the CAM industry’s leading subject specialists. Camexpo’s exceptional CPDaccredited education programme includes the latest research and advice to advance your business. We will be on stand 2116, so do come and say hello. Registration is £6 for ION members by registering here or by using priority code: CAMNo421

References

1 Eriksson N, Wu S, Do CB, Kiefer AK, Tung JY, Mountain JL, Hinds DA, Francke U (2012). Preprint at http://arxiv.org/abs/1209.2096

2 Hansen EA, Folts JD, Goldman IL (2012). Steam-cooking rapidly destroys and reverses onion-induced antiplatelet activity.

Nutrition Journal; 11:18pp.

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