Shift work and health: the Cliff notes.

I’ve worked in a wide variety of jobs in my life. Like many people, I spent the latter part of my high school and university years cleaning toilets, clearing tables, washing dishes, delivering pizza and making sandwiches when there was only one sandwich maker in town. Subway, George St. Aaah….the memories. Somehow I was always put on the graveyard shifts of Thursday night 8pm-4am and Saturday 10pm-6am. Though it totally went against my natural tendency to be early to bed, early to rise, they were the most fun shifts to work. As one of the few places open 24 hours over the weekend, we got queues out the door of students either rolling in from the Cook or stumbling home from KCs, with the busiest period being from 2.30am to around 4am. I still remember the excitement at serving both a glazed eyed Marc Ellis and Rachel’s brother Jonathan from Shortland Street – before seeing Shorty stars was as ho-hum as …. seeing Shorty stars. Anyway. I’d get home either 4.30 or 6.30 and sleep 5ish hours before getting up and try to get back into a daytime routine. I always felt rubbish through lack of sleep and so thankful that I wasn’t pursuing a career that required me to do shift work.

Now, though, amongst the industries that have always needed to be available 24/7, the global society we live in now necessitates other occupations to put in hours that extend beyond the 9-5. The prevalence of employees working shifts in the media, healthcare industry, on the front line and in the corporate world is estimated to be around 20% and the available data in New Zealand is in line with this. This is a large subsection of the working population, and why it’s of note is that there are well established links between shift work and poorer health outcomes – both short and long term. The constant sleep deprivation that results from shift work is a major underlying issue.

The most important things we can do to help mitigate the effects of chronic sleep deprivation that occurs due to shift work (aside from actually sleeping!) are the very things that go out the window. A regular exercise routine is more difficult to maintain, due to tiredness from lack of sleep or the inability to structure if you are on a shift cycle that changes from day to night. Eating healthily is more difficult as having motivation to plan and prepare is more challenging, and often the pull to higher sugar, poorer nutrient foods is governed by cravings and accessibility. In addition, perhaps overlooked, maintaining relationships can be more difficult as the non-sociable hours of shift work impact on our availability to spend time with friends and family. Hanging out with John on the 5th floor is not the same.

It’s also well established that the affects on circadian rhythm put shift workers at a higher risk of many chronic diseases. Up until 150 years ago we were constrained by the natural sunrise and sunset and life on earth had evolved according to this. When artificial light was invented there were suddenly more hours in the day that could be spent being awake, and the shift in our wake and sleep cycle impacts on metabolism, hormones, digestion, cardiovascular system; in fact all of our cells in our body is affected by this. Sleep deprivation in the short term increases insulin resistance – it takes just a single nights’ sleep for this to occur. There is an increase in the risk of injuries on the job, and a link between both acute and chronic gastrointestinal problemsMood disorders are also associated with circadian rhythm disruption, and both observational and experimental data point to an increased risk of obesity in shift workers due to these circadian rhythm changes.  Over the long term, there is an increased prevalence of risk factors associated with the metabolic syndrome, type 2 diabetes, cardiovascular disease and cancer are all seen in shift workers compared to those who keep a more normal work schedule.

While you might think people who are early risers would be more negatively affected by shift work, this hasn’t been found to be the case.  Research shows that those who are late risers have lower levels of melatonin (a hormone that mediates the sleep-wake cycle); the suppression of which is one proposed mechanism for the increased health risks associated with working hours that disrupt circadian rhythm.

So what to do? Obviously, being able to opt out of shift work is not realistic for the 20% of the population who live and work in this 24 hour society. This report details the interventions in the research setting that have been found to be most beneficial. These include scheduling shifts to be ‘forward’ shifts rather than backward shifts (i.e. moving from a morning, to an afternoon, to an evening shift), avoiding stimulants such as coffee (in excess) and wearing light blocking eyeglasses on the way home from night shift. Sleeping in a dark room and wearing an eye mask will also help.

Along with the above, ensuring good sleep hygiene practices through both diet and exercise are essential. Though it might be the last thing you feel like doing if you’re just getting into exercise, a routine that you stick to will go a long way to helping you mitigate these effects. Exercise is so important for everyday health and well being, that to ignore it would only further exacerbate some of the health issues mentioned above. Further, in the face of sleep deprivation and acute insulin resistance, strength training helps improve insulin sensitivity and may minimise the blood sugar disruptions experienced. As mentioned, coffee is likely one of the first things you go to when you feel like you need an energy hit, but instead of this, why not try green tea – it has L-threanine in it which helps keep you alert without the caffeine hit. Perhaps save coffee for your days off (and limit to just one); dare I say it – try a decaffeinated brand otherwise. Some companies like to supply food for their employees, and this tends to be cheap plain biscuits, white bread and jam, and other types of food to provide a quick hit of energy when time is of the essence and there is no time to stop for a real meal. These options, along with the vending machine, are the last foods you want to be eating. On your off days make it a habit to prepare two or three ‘dinner’ like meals that you can freeze and eat throughout the week. Trying to structure your whole food, minimally processed meals so they are ‘dinner’ like at dinner time (before you head into a night shift, perhaps), lunch like in the middle of your shift, and then a lighter meal before you hit the sack in the morning will maintain the regularity of meals regardless of whether you’re working or not. Being prepared with your good food options means you can avoid those that are available at work. In addition, a magnesium supplement (with an amino acid or citric acid chelate) before bed can help promote good sleep. Finally, if you are constantly waking up, practicing some deep breathing in bed can help calm you down and send you back to sleep. Diaphragmatic breathing will decrease your sympathetic nervous response – ‘fight or flight’ and the levels of stress hormones entering the bloodstream which are released because of this which could prevent you falling easily back to sleep.

Shift work is a necessity for many people, and some fare better than others. If you are a shift worker who fares fairly well despite the disruption in sleep and subsequent poor lifestyle habits you may not feel that these tips would apply to you. However maintaining your health is as important now to offset the long term effects of shift work.

Snapshot of the brain 2 (and a bit of a related, but slightly off topic vent).

Now… where was I? Oh yes. The brain. As I said in my brain post three weeks ago, it’s not just calories and energy required to fuel it – in fact, if that’s all that you relied on, your cognitive function would diminish, brain fog would ensue and overall brain mass would reduce. Seriously. The importance of a nutrient-rich diet cannot be overstated when it comes to a healthy body and mind, at which the brain is at the centre of. The myriad of reactions and interactions of nutrients in the brain is too involved for me to adequate write up here, and as you know, scientific scribe is not how I roll, so this is a very brief overview, combined with a bit of a vent (my favourite).

In order to convert the calories provided (either by glucose, fat or lactate) into ATP for the mitochondria to use (energy to be produced), riboflavin and niacinamide (B vitamins), Co-enzyme Q10 (not just good as part of a skin cream) and magnesium are required to enable reactions at various stages of the process. Antioxidants are also required to scavenge free radicals so they do not damage cellular tissue through oxidation. The B vitamins and amino acids are important as neurotransmitters to send messages from the brain to various parts of the body. Magnesium is like a super mineral – involved in over 300 processes in the body – it has a really important role in the brain, acting as a ‘guard at the gate’ if you like, blocking excess calcium and glutamate from entering the cells. Both of these can increase cellular damage due to their excitatory effects in the brain. Magnesium also exerts control over the hippocampus, preventing it from stimulating the release of adrenocorticotropic hormone, or ACTH. ATCH instructs our adrenal glands to pump out both cortisol and adrenaline in times of stress, and magnesium inhibits these hormones from entering the brain and causing additional cellular damage. Thank you, magnesium, you’re not just good for relieving constipation and regulating insulin sensitivity.

Vitamin D has a neuroprotective role, promoting their survival and reducing damage – hence its association with the preservation of cognitive function in the brain. It helps reduce inflammatory factors related to neurological disorders such as multiple sclerosis and there is an association between vit D levels and depression – with receptors for the active form of Vitamin D found in the hippocampus.

Vitamins C and E are antioxidants, and clinical trials have shown that adults who supplement these two vitamins improve their cognitive function when compared to a placebo group. Iodine has been found to be particularly important in the development of the brain, and if a pregnant women has an insufficient intake of iodine, their baby may be born with a low birth weight, cognitive impairment and their physical development impaired. Sulfur is another component that contributes to antioxidant activity and acts as a neuroprotector in the brain.

Docohexanoic acid (DHA) is a long chain fatty acid that is found pre-formed in fatty fish such as salmon, sardines and mackerel. It may be the most studied nutrient with regards to the brain and is the most abundant omega 3 fat found in the cell membranes of the brain. Our body is not good at synthesising it and the conversion of it from plant-based sources such as alpha-linoleic acid is poor. It’s important for ensuring membrane fluidity, protects membrane integrity and is involved in the development of synapses. Indeed, archaelogists suggest one of the pertinent factors in humans having an encephalisation quotient as big as we do is largely due to early populations living close to the shore line and having access to marine life. Associations have been drawn between fish consumption and neurological function. In addition, in health older adults, more essential fats , vitamins and minerals present in bloodstream is associated with bigger brain, better cognitive test. Higher intake trans fats and processed food – smaller brains, lower cognitive function.

So when you do hear ‘a calorie is just a calorie’ as is often touted, particularly in the weight loss arena where the argument of a calorie restricted diet versus the nutrient-focused diet is often played out, you can see that this just isn’t true. A calorie restricted diet is often too restrictive, not only making fuel availability questionable at certain times, but not focusing on the right macronutrient calories – given that carbohydrate is much less calorie dense than fat. In addition, the focus on calories shifts attention away from the all important micronutrients I’ve listed above (among others) which are essential for brain functioning and (importantly) overall mood and wellbeing. No wonder those on a 1200 Calorie diet counted by adding up the numbers on the back of their cereal boxes, muesli bar wrappers and diet yoghurt containers don’t get the same feeling of calm and nourishment that comes when following a real food approach. The addition of nutrients to cereals by way of fortification doesn’t help – particularly if the delivery vehicle is a cereal that has additional gluten added to bump up the protein content (i.e. Special K; a topic deserving a blog post all on it’s own). Unfortunately when we consider all of the elements that promote and preserve brain health in light of what people are actually buying, then it doesn’t make for a pretty picture. Take this for example – the top 10 foods sold by volume in supermarkets in 2009. Bar the bananas, all foods on the list are nutrient devoid.


Thanks, Jamie for this info.

In NZ currently, we have children who are over-represented in both the low academic achievement rates and the lower socioeconomic sections – these are interlinked obviously. Further, these children tend to have a poorer diet – with less fibre, less calcium, less fruit, cheese and milk than their school-aged peers. As these foods are important contributors to the aforementioned nutrients above, is it any wonder that those most disruptive in class, less likely to achieve academically are less likely to finish high school? There are clear links between diet and hyperactivity, concentration, and even cognitive development – the available nutrients include those delivered from the mother prenatally. How are these children supposed to further themselves if they don’t have the right start in life.

Yes, in NZ we have the Fonterra breakfast in schools programme (Kickstart) – now funded and widely available to those less privileged in decile 1 schools. Is it better than nothing at all – yes? Are weetbix and milk the best we can do? I don’t think so. What about government funded school based gardens/kitchens? What about attention in the curriculum to teach children the fundamentals of good nutrition, perhaps through an integrated curriculum? Teach them the importance of it in an environment that supports it – not in one where all attention is pushed towards ‘energy out’ physical activity model. School Food and Beverage guidelines? Bring it. Much better than the voluntary system that is in place now in schools. All of these take time, resources, investment – the government has a $40 million healthy lifestyles initiative which looks at supporting communities to make healthier choices, which – if included the above – could be promising. However the first sentence on the website doesn’t fill me with much hope: “Encouraging families to live healthy lives – by making good food choices, being physically active, sustaining a healthy weight, not smoking and drinking alcohol only in moderation – is part of the Government’s approach to promoting good health.” Not because I don’t think the government should be doing this – but this is no different from what they’ve always said. People need more than encouragement – they need infrastructure to make it easier. Anyway, let’s see.


Feeling SAD?

Damn. We Aucklanders are getting our share of terrible weather. That’s the problem with being smug and posting pictures of our awesome non-winter winter climate… eventually it comes back to bite us in the butt. Usually in spectacular fashion: this week has been almost torrential storm-like conditions, with power outages and garden furniture strewn across the driveway (or is that just me?) Naturally this dip in temperature to below 15 degrees comes with it a sense of gloom as the sun fails to make an appearance. Grey clouds are oppressive, huh? Does that make you feel a bit blue? It does me – once the temperature drops and I haven’t seen the sun in four days I feel utterly miserable, diagnose myself with mild depression, and more specifically Seasonal Affective Disorder – or SAD. It’s a particular type of depression that starts in the autumn and doesn’t let up until the daffodils are out. In reality, I don’t think I would be diagnosed with SAD, and population prevalence is in the realm of 1-12% depending on your location, a higher prevalence in areas with longer winter days and lack of sunlight hours (one reason why I couldn’t live in ‘middle England’; not only does it sound horribly dull (it’s up there with ‘original flavour’) but daylight hours are limited during winter. And I know it’s worse elsewhere). But I digress. However, I feel a bit blue all the same.

Interestingly, there are two types of seasonal affective disorders – some curious people feel more depressed in summer than they do in winter, therefore the reverse is true. That to me is like a fate worse than death, quite frankly. Up there with Man Flu. SAD is diagnosed by the presence of symptoms such as: 

  • Decreased energy levels
  • Difficulty concentrating
  • Fatigue
  • Increase in appetite
  • Increased desire to be alone
  • Increased need for sleep
  • Increased irritability
  • Increased anxiety
  • Weight gain

Scientists have pinpointed a few reasons why the lack of sunlight can disrupt our mood. This is largely due to our levels of melatonin – this is a hormone which plays a role in how our body regulates its sleep/wake cycle. The longer periods of darkness in the winter months may stimulate melotonin production and potentially people with SAD overproduce melatonin or are hypersensitive to melatonin in the winter months. While melatonin is recommended on an infrequent basis for people who struggle with sleep (for example, during periods of travel where jetlag can set it), too much melatonin can result in headaches, day time sleepiness, and depression.

Other evidence shows that decreased levels of neurotransmitters (chemicals that transmit signals between nerve cells) such as serotonin or dopamine may also play a role in triggering SAD. Low levels of serotonin in particular have been associated with carbohydrate cravings in people with SAD, and with sleep disorders and depression in the population at large. So not only does the reduced amount of serotonin trigger carbohydrate cravings (carbohydrate facilities the production of serotonin), this subsequent increase in food intake can lead to weight gain and further feelings of despair. Lose-lose, really. Even in those that don’t feel particularly blue during winter, the stodgy, starchy carbohydrates that can lead to weight gain and increased carbohydrate cravings are the warming foods we naturally gravitate towards.

As serotonin is largely produced in the gut I went searching for studies that looked for a link between digestion and SAD, as without the nutrients required to produce serotonin – including tryptohan which is an amino acid and key in the process – levels will be lower. I didn’t come up with any though, but with the clear link between the gut and brain, it makes sense that there would be.

Lastly I also found interesting relationships between SAD and other conditions. It’s not just weight gain that could be a problem – A Finnish study found there was a significant association between seasonal changes in mood and behaviour and metabolic syndrome, with risk of metabolic syndrome increased by 56% in those with seasonal affective disorder. The researchers noted that the metabolic syndrome is related to changes in the circadian rhythm – and that circadian, sleep-wake and seasonal cycles may each be regarded to reflect an intrinsic metabolic cycle. Sleep onset is a switch for the metabolic and cell repair systems from daytime to night-time settings and if the right signals aren’t there, the circadian clockwork relies more on the metabolic cycles producing time-giving signals needed for adaptation – insulin plays a role in this and helps set the circadian rhythm.

So what treatments exist for helping improve melatonin and serotonin levels and hopefully offset the low level depression that many people experience?

Light therapy: helps with regulating melatonin production and can indirectly affect serotonin levels by blocking the mood-lowering affects of acute tryptophan depetion. exposure to intense light in the early morning has been found to be most effective, as this suppresses melatonin. The treatment involves sitting in front of fluroscent lights which are installed behind a diffusion screen, and carrying out normal activities for anywhere from 30 min to 2 hours depending on the intensity of lights. The critical factor is that the light matches that of either early morning or just before sunset. he dosage most often found to be effective is 5,000 lux per day, given as 2,500 lux for two hours or 10,000 lux for 30 minutes. This isn’t just sitting in front of a desk lamp.

I talk about sleep all the time… but in addition to adequate sleep, getting up and going to bed at around the same time most days can also help regulate levels of melatonin, particularly combined with the light therapy as above.

Get outside and exercise: it might be the last thing you feel like doing but honestly – nothing is as energising and invigorating as getting outdoors, particularly in cold, windy, inclement weather. This helps boost serotonin levels by increasing availability of tryptophan to the brain. This is particularly important as we tend to spend a lot of time inside. The added bonus here is getting natural light – this helps boost overall mood.

Fight against the desire to stay at home and make plans with friends or family. It’s all too easy to hibernate, inevitably making you feel worse.

Diet: while there are foods that are high in serotonin or tryptophan, few actually cross the blood brain barrier to enable their action in the body to improve mood. Typically high protein foods containing tryptophan were recommended, though this doesn’t actually increase serotonin levels in the brain when studied  , as amino acids compete for transportation in the body and most protein containing foods are relatively lower in tryptophan than other amino acids. Hence perhaps changing the ratio of tryptophan to other amino acids is useful, and research has shown that supplementing with a dietary protein alpha-lactalbumin (a constituent of milk) can increase serotonin through this strategy. While interesting, it’s not very practical for people in every day life. Insulin helps set the circadian rhythm and perhaps a diet that focuses on high protein for breakfast and lunch, with small amounts of carbohydrate at night can maximise insulin secretion at night and help appropriately reset circadian rhythm. Unsurprisingly, the importance of a whole food diet rich in nutrients to support digestion and absorption of nutrients cannot be overstated given the link between serotonin and mood.

Oh, and hopefully the increased protein, the exercise and the sleep helps you combat those carbohydrate cravings. In addition to this, find some equally warming winter substitutes. It’s not like you need to completely avoid carbohydrates at all (see above re insulin) – it’s about avoiding Richard Dreyfuss amounts of the white stuff. That’s not going to make you feel any better I promise.

  • Mash: cauliflower mashed with butter or olive oil, herbs and seasoning.
  • Fries: slice swede and boil until a little bit soft. Dry off and coat in coconut oil and some almond flour and roast. Or just roast from raw.
  • Pasta: zucchini noodles (or as my friend Helen likes to call them: courgetti) or use leeks (cook)
  • Rice; cauliflower rice

There are certainly people who are diagnosed with SAD, and equally there are people (like me) who wouldn’t meet the diagnostic criteria yet still feel a bit less awesome. All of the above tips then will help you keep feeling awesome over the winter months. And we are almost half way through! That’s enough to make me feel happier :-).


How do I rate the Health Star rating system?

So this is a slight departure from scheduled programming. I will get back to the nutrients in the brain, I promise. Like next week. However the unveiling of our (NZ’s) plan to adopt Australia’s star system in order to rate the ‘healthiness’ of food kind of got me thinking. Not a lot – don’t worry. But a bit. So this will likely be brief and hopefully give you something to ponder as you sip your latte and read the paper (or run after the kids down at the gardens while feeding the ducks stale bread – which really is where any white bread product belongs, quite frankly). Essentially, the health star rating is designed to be an easy to understand panel for consumers to evaluate the healthfulness of a product. It is designed to be interpretive, which would ideally take the guess work out for people who want to make healthier decisions around food. It is designed around the UK nutrient profile system. It’s front of pack labelling gives people at-a-glance access to the nutrition information, and takes into account overall energy content of the food, the saturated fat component, sodium and total sugars. It also highlights positive features such as dietary protein, fibre and its fruit and vegetable content. It uses a star rating of ½ to 5 stars, and those with more stars are supposed to reflect better choices:

Star rating

The two choices: Either in relation to % daily intake (above) or per 100g

Another rating system for food. And, with it, comes a few issues. Saturated fat for example. In the context of a whole food diet, the inclusion of saturated fat is not likely to increase the risk of diet-related disease in all but a few individuals (and that’s quite a blanket statement, but reflects the state of our knowledge at this point in time). However, the difference in saturated fat content between reduced fat and whole milk, margarine and butter, and the content of cheese totally blows out the star rating of some really nutritious food and labels foods ‘healthy’ which are highly processed, high in industrial seed oils or have had some of the healthiest nutrients removed to create a lower fat option (milk). The saturated fat content of packaged, processed food? Totally deserves to be labelled as ‘to be avoided at all costs’. In this context, the food item delivering the saturated fat is likely also high in processed refined carbohydrate (sugar, flour), lower in fibre and overall nutrients. Think crackers. Or Eta Munchos. Or those food products that used to only be a ‘treat’ chocolate product which have infiltrated the biscuit aisle and are now masquerading as morning tea. Yes, Freddo, I’m looking at you.

Lurking at a biscuit aisle near you.

Lurking in a biscuit aisle near you.

Another issue – as far as I can see – is that it’s voluntary for manufacturers. Not only do they not have to use it, but they also have their choice of labelling. They can have it either as a per 100g serving or as a percentage of daily intake – and apparently for the whole packet? I really don’t like these % labels and they are everywhere. Cereal companies love them. Percentage of who’s daily intake? This whole concept is entirely confusing for all concerned. People don’t understand food labels, or energy requirements. You might – you are, after all, reading my blog which suggests you have at least a fleeting interest in it – but believe me, the general population don’t. This report from food standards new Zealand summarises that and, interestingly, also states that even when given information to enable them to understand percentage labelling better, consumers didn’t really use it. Indeed Australian research reveals the same thing Tellingly, only those who were interested in nutrition actually used it. So… exactly the people that don’t need it. And how much does a packet serve? Some of these seemingly individual products do – on closer inspection – feed a family of eight, not just you at morning tea. If you’re looking at the health star rating and thinking you may have seen it before, then you won’t be too far wrong… it looks just like almost every other front of pack labelling that is used by companies such as the aforementioned cereal companies. People don’t do details. There’s no real distinction between the rating deemed by the Ministry of Primary Industries to give us useful information and that which is created by the manufacturer, designed by them to be read as they want us to read it. Companies who aren’t in the business of health, but in the business of selling us product. For a star rating to be effective, perhaps the removal of very similar manufacturer labels be compulsory to help minimise confusion. Finally – for a product to have a star rating almost gives it a health halo akin to that of the Heart Foundation tick. We may know that a tick is as flawed a concept as the Glycaemic Index symbol, but others look to it as a healthy product. The devil is in the detail – it might be lower in energy, lower in sugar and lower in sodium, but we know it doesn’t make a product ‘healthy’ – just more favourable in comparison to a like product. Those are details that we as health advocates are well aware of. The general public? Not so much. On that note, did I already mention that the National Heart Foundation have unveiled another tick system? Yep, that’s right. Not content with just one tick, they have introduced the two tick system. Two ticks. Must be even more healthy, right? Core food groups are worthy of two ticks, these other products are only able to get one tick. As I’m looking at these two groups I have two thoughts: 1. Why do these foods even need a tick? 2. How on earth did some of these foods get one tick in the first place? Hmm. Yes. A health rating on a food item is problematic. If I had my way, real food wouldn’t need a label (obviously) and any labelling that packaged food has should be related to the degree of processing, the amount of additives, it’s shelf life, and the combination of nutrients known to affect health (i.e. fat and sugar). That would get my tick of approval and five star rating. 🙂