Caffeine is used widely around the world, be it as a stimulant for mental or physical performance, mood enhancer or flavouring. However, its use can also give rise to negative effects, such as sleep loss, headaches, withdrawal-like symptoms, and in the case of caffeine overdoses, hospitalisation and even death. Currently no data exists in NZ examining the interactions between how much caffeine people consume, the sources of caffeine ingestion and the reasons for this intake. This study will develop a questionnaire examining these issues, which may be used in future projects to understand caffeine intake in the wider NZ population. The questionnaire will be developed using data collected from a series of focus groups run as part of this research, where a variety of people from different backgrounds will be involved in group discussion on caffeine consumption patterns.

Student: Karli Rowe (MSc Nutrition and Dietetics)

Collaborators: Dr Kay Rutherfurd-Markwick and Dr Carol Wham (Massey University)

The positive effects of caffeine intake are well known, whereas the negative effects of caffeine intake aren’t as widely recognized.  Recently it has been found that the risk of side effects has a large genetic basis. One of the most studied caffeine related genes is CYP1A2 which codes for the enzyme that metabolises caffeine- cytochrome p450. This enzyme is also responsible for the metabolism of multiple other drugs. There are three variations of this gene which determine whether an individual is a slow, intermediate or fast metaboliser of caffeine. Slow metabolisers are considered to have a higher risk of the negative effects of caffeine due to caffeine remaining in the blood stream for a longer period of time. One variant of this gene has been associated with an increased risk of myocardial infarction (heart attack). Another gene with an established relationship to caffeine is the adenosine receptor gene, ADORA2A. A variation of this gene has been found to be associated with Panic Disorder. This same variant has been associated with caffeine-induced anxiety, sleep changes and caffeine sensitivity. There is currently very little information about caffeine intake and the reasons behind the consumption of caffeine in New Zealand. New Zealand has an ever-growing supply of caffeinated products on the market, making this is a very important research area. This study aims to gather information on the caffeine consumption habits, knowledge, beliefs and responses of young New Zealanders with the use of a questionnaire (Caff-Co). In addition, genetic testing will be carried out with the use of saliva samples. This information will help to determine groups who are at the most risk of suffering the ill-effects of caffeine consumption.

Student: Saskia Stachyshyn (MSc Nutrition and Dietetics)

Collaborators: Dr Kay Rutherfurd-Markwick and Dr Carol Wham (Massey University)

Although the effects of caffeine has been well covered in the scientific literature, the emphasis has been on the physiological, metabolic, and hormonal effects within the body. Few caffeine studies have investigated the influences and drivers for consumption of caffeine intake, especially in sportspeople.  Therefore, in the present study, the reasons and motivations behind caffeine consumption in New Zealand adults that play sport, along with the effects of genetic, social, and environmental influences in this group, will be examined.

Student: Jackson Chien (MSc Nutrition and Dietetics)

Collaborators: Dr Kay Rutherfurd-Markwick and Dr Carol Wham (Massey University)

Caffeine has for several decades been shown to provide an ergogenic effect on exercise performance when taken in the correct dosage. However, the effect of caffeine on performance varies between individuals. Several genes have been linked to caffeine metabolism; among these genes is the CYP1A2 gene which is found on the cytochrome P450. Some research suggests that ‘fast’ metabolisers of caffeine (homozygous A variant allele) may show better performance benefits relative to ‘slow’ metabolisers of caffeine (C variant allele). The purpose of this study is to investigate the effects of caffeine intake and genotype on exercise performance, metabolism, immune function, mood and sleep in male recreational runners.

Student: Kyle Southward (MSc Sport and Exercise Science)

Collaborator: Dr Kay Rutherfurd-Markwick (Massey University)