My Anti-Cancer Eating Plan

Our media rarely stop buzzing with reports about anti-cancer foods. Each time a study suggests that a particular berry, nut or spice may have anti-cancer properties, journalists hail it as a new wonderfood and everyone rushes out to buy it.

As a nutritionist, I welcome information that heightens the public’s awareness about healthy eating. However, when recommendations are contradictory they can become counterproductive.

After years of being told to eat five fruits and vegetables each day, health-conscious eaters were stunned to learn recently that these foods apparently offer only scant protection from cancer. (I will address this in a separate post.) Similarly, while some research suggests that soy food has a cancer-protective effect, other investigations haven’t backed this up. Indeed, some observers warn that soy foods, which contain estrogen-like compounds, may actually stimulate estrogen-sensitive tissues and could thereby promote, rather than prevent, cancer.

It’s not surprising, therefore, that many people feel overwhelmed when trying to figure out what they should eat to help prevent – or recover from – cancer. Indeed, some are so confused by contradictory reports that they stop believing anything they read in the press and revert to their old eating habits, as a recent survey showed.

When putting together my Anti-Cancer Eating Plan, therefore, I decided to base my program on the most unambiguous and reliable data I could find: the World Cancer Research Fund’s Expert Report published in 2007, which analyzes tens of thousands of studies into the food-cancer link and offers practical recommendations based on the findings.

At first sight, the WCRF’s recommendations may seem a little conservative. For instance, their researchers could not find clear evidence that soy, green tea or turmeric – widely touted as anti-cancer foods – are in fact cancer-protective. At best, the WCRF concluded, “there is limited evidence suggesting that pulses, including soy and soya products, protect against stomach cancer and prostate cancer”. Green tea and turmeric were mentioned only in passing. Note: the WCRF report does not say that we should not consume these foods; it simply notes that there is not enough evidence to say that they offer protection from cancer.

What appeals to me about the WCRF’s recommendations, however, is that they are realistic and achievable for almost anyone. For whilst anti-cancer diets involving exotic, unfamiliar or expensive ingredients may suit some people, most of us when faced with excessively challenging dietary change give up and go back to our previous eating habits. Smaller but realistic steps in the right direction may be more effective and sustainable than drastic changes that don’t last. Besides – to some people, implementing just one or two of the WCRF’s recommendations (below) will feel plenty drastic!

My Anti-Cancer Challenge Eating Plan will thus be based on the following dietary recommendations issued by the WCRF:

• Avoid sugary drinks and limit consumption of energy-dense foods (particularly processed foods high in added sugar, or low in fiber, or high in fat)
• Eat more of a variety of vegetables, fruits, whole grains, and pulses such as beans
• Limit consumption of red meats (such as beef, pork and lamb) to no more than 500 g (cooked weight) per week, and avoid processed meats
• If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day
• Limit consumption of salty foods and foods processed with salt (sodium); do not eat more than 6 g salt per day (about 1 teaspoon)
• Don’t use supplements to protect against cancer (exceptions being women planning to conceive (folic acid); vitamin-D-deficient people, and people whose low appetite (illness) or low calorie needs (the elderly) restrict their nutrient intake (a good multivitamin).

Other suggestions and practical tips from the WCRF include:

• Balance your plate: 2/3 of your plate should be of plant origin and 1/3 of animal origin.
• Fish is a healthy alternative to red meat; eat it regularly. Some limited evidence has shown it may help to protect against bowel cancer. 
• Poultry (chicken, turkey, duck – skinless where possible) and other lean meats such as rabbit and venison are healthy alternatives to red meat.
• Cooking methods: baking, boiling and steaming are healthy cooking methods; other high-temperature cooking methods may alter the make-up of foods, especially meat. It is prudent not to consume burned or charred foods frequently or in large amounts.

In order to tailor the Anti-Cancer Challenge Eating Plan to my family’s needs I added a few more items:

• Dairy foods: The calcium in milk may protect against bowel cancer, but milk consumption has been linked to an increased risk of prostate cancer. Moreover, my daughter is allergic to cow’s milk. Therefore I limit cow’s dairy and consume only goat’s and ewe’s milk cheese and yoghurt.
• Foods rich in omega-3: This essential fatty acid is thought to have anti-inflammatory and anti-cancer properties. I eat omega-3-rich foods daily; these include oily fish (sardines, mackerel, salmon, anchovies, herring), ground flax seed, green leafy vegetables, and eggs, meat and dairy from animals fed an omega-3-rich diet. I avoid large fish (tuna, shark, swordfish) because of their potential contamination by mercury or other marine pollutants.  
• Green and white tea: epidemiological studies and laboratory studies in animals and on human cancer cells suggest that green tea may protect against cancer. Since I enjoy its taste, I drink two to three large cups of green or white tea daily.
• Vegetables and fruits: I eat a wide variety of vegetables and fruits, including all members of the cabbage and onion families, mushrooms, red and blue berries, citrus fruit, sea vegetables and carotene-rich vegetables & fruits (e.g. tomatoes, carrots, melon, winter squash, etc). I eat at least 5 portions a day, but I'd like to increase that to 8 a day in the course of the Anti-Cancer Challenge.
• Herbs and spices: I make copious use of fresh kitchen herbs that I grow in my garden or buy at the market (parsley, thyme, coriander, chives, basil, rosemary, oregano) and which are rich in anti-oxidants. I use many different spices such as turmeric, pepper, chili, cinnamon, coriander, cumin, cardamom, paprika, saffron and ginger. The copious use of herbs and spices is a great way of boosting the flavor of many dishes without needing to use salt.  
• I eat seasonal, locally-grown foods: In order to obtain the freshest produce, protect the environment and support the local economy, I buy most of my food (about 75%) at the nearby farmers’ market and directly from local producers. If it’s not in season (e.g. tomatoes in January, cabbage in July) I don’t eat it. I grow some vegetables in my own vegetable patch.
• About 80% of the meals I eat are prepared at home, from scratch: I do not buy prepared meals or processed ingredients except for plain vegetables in jars or cans (e.g. tomatoes, lentils, beans) and occasional condiments (e.g. pesto, ). All meals are eaten at a table, with all family members sharing the same meal. The television is off while we eat and I do not eat in front of the computer or while driving.

Overall, I am happy to say that I already do most of these things. I rarely eat red meat (about 150 g per week at most) and consume lots of vegetables and fruits and small amounts of whole grains. I drink only red wine (a glass with dinner on weekends), and use very little salt in my cooking. 

Not taking supplements will be interesting; for the past 10 years I have taken a pretty high-dose multivitamin supplement and fish oil capsules, and I am curious to see whether not taking these will make any noticeable difference to my health and well-being. No longer being able to rely on the "health-insurance effect" of my supplements will make it imperative that everything that enters my mouth is as nutritious as possible - no room for "empty calories". 

Do you have any dietary cancer-prevention advice that you would like to share with readers? All suggestions welcome!

Food for Life

A keen cook and a self-confessed glutton, I have always been passionate about the selection, preparation and enjoyment of food, though for a long time, the accent was on "pleasure" rather than on "health".

My brush with cancer 10 years ago made me realize that a healthy diet isn't an optional extra but a vital necessity. And so I began eating as though my life depended on it.

While my health has indeed improved, I have been particularly pleasantly surprised to discover how enjoyable a healthy diet can be! To me, fresh, natural food, simply prepared, is incomparably more satisfying and pleasurable than the fatty, crispy, gooey treats I used to delight in. Hold the onion rings - I'll have some crunchy spears of asparagus drizzled with olive oil and lemon juice and dusted with light parmesan shavings, thank you. (What's more, I'll save on antacids!)

Most people, when they think of cancer, rarely think about food. Many hold the fatalistic belief that cancer is largely programmed by our genes and that there's nothing we can do about it (in fact, at most 15% of cancers can be attributed to genetic causes). Even those of us who are aware that life-style plays a critical role in cancer usually think of smoking, alcohol consumption or sun exposure as the main risk factors.

But few consider food as a factor that may contribute to causing cancer. And yet, it is increasingly understood that diets rich in sugar and refined carbohydrates, unhealthy fats, red and processed meat and deficient in nutrient-rich vegetables, fruits, nuts, seeds, herbs and spices, may increase our cancer risk.

Once cancer has been diagnosed, most people embark on the recommended medical treatment: surgery, chemotherapy, radiation therapy or a combination thereof. Very few doctors recommend dietary measures as part of conventional cancer treatments. Medical students are taught only the bare essentials of nutritional science.

Nevertheless, nutrition plays a crucial role, both in preventing and in overcoming cancer. In its landmark Expert Report, the most comprehensive report ever produced on the links between lifestyle and cancer risk, the World Cancer Research Fund (WCRF) estimates that up to 30% of all cancers could be prevented by eating an optimal diet, getting regular physical activity and maintaining a healthy body weight.

Some experts even suggest that some of the commonest forms of cancer, such as breast-, colorectal and prostate cancer, could be reduced by 60-70% and lung cancers by 40-50% if people ate an anti-cancer diet. Even cancer patients undergoing treatment may find this type of diet helpful, some studies suggest.

A healthy diet is certainly not a stand-alone treatment for cancer, nor is it a fool-proof tool for prevention. Modern medical approaches are an essential part of any cancer therapy. Nonetheless, what and how you eat before, during and after cancer treatment can have a crucial impact on its outcome.

Meanwhile, for those of us who are healthy but worry about becoming ill - without prevention, about one in three women and one in two men will develop some form of cancer during their lifetime, the U.S. National Cancer Institute predicts - it's important to know that changes in diet can very much tip the odds in our favor.

By the way, healthy eating isn't just for cancer patients. There are benefits to everyone in a diet that boosts general health and well-being. Thus, an "anti-cancer" diet can potentially help prevent or relieve a long list of other medical conditions, including diabetes, heart disease, dementia, arthritis and even depression.

In addition to helping improve overall health, the anti-cancer diet I follow has no known negative side-effects. In my experience, if there are any "side-effects," they are increased energy, fewer colds and sore throats, clearer skin, better digestion and a happier disposition. Fine with me!

In my next post I will unveil my Anti-Cancer Challenge eating plan for the remaining 11 months of this project, so watch this space.

Month One : Progress Report

It’s been just over a month since I began the Anti-Cancer Challenge. Here’s my first progress report.

(If you have recently joined the Challenge, you can consult my Fitness Plan here and my Sleep Plan here; there are also links to these pdf documents in the right-hand column. I plan to post my Diet Plan this week.)

1.    Exercise 

As planned, I have been exercising every day for about 30 minutes. On some days I have done shorter, more intense workouts, and have thrown in other additional activities such as lawn mowing (very tiring when you don’t know how your new lawnmower’s automatic traction works… My 12-year-old showed me after I had nearly finished mowing our rather expansive lawn!). The only interruption to my exercise routine (past two days) came from stepping on a rusty nail and driving it through my shoe and foot while lawn-mowing (ouch!).

I still struggle to make time for my workouts at the start of the day – I often get distracted by other seemingly important and urgent matters (work, housework, phone calls and other procrastination techniques) and don’t get around to exercising much later in the day, at which point I feel much less energetic. Over the next month, I aim to exercise first thing in the morning, no matter what my house or e-mail cue look like, so I can shower and move on to other things without a guilty exercise deficit hanging over my head.

What has come as a very pleasant surprise is discovering just how invigorating even short spurt of physical activity can be! Not only do I feel proud of myself whenever I have managed to overcome my resistance and moved my body. At a physical level, too, I feel more energetic, more bouncy and resilient. Instead of increasing my desire for food, as I had expected, I’ve noticed that my appetite seems to be curbed for at least 2-3 hours after exercising – quite unusual for a habitual snacker like myself. (Perhaps also because I feel good about myself and don’t need to boost my morale with the help of chocolate…)

Another positive surprise is the fact that little exercise can go a long way. A mere 20-30 minutes’ activity each day (indoor rowing, jogging, weights exercises – all done at moderate intensity) has made a palpable difference to my body shape: certain clothes that felt very snug no longer do so, and I feel stronger and less easily winded. My arms, especially, feel stronger, and the wobbly under-arms I was beginning to fret about as the t-shirt season approached (my son recently called them “Mama’s jelly-arms”) have firmed up. Phew!

2.    Sleep

Writing down all my good intentions was the easy part; now I have to actually put them into practice! I have found it very challenging to get seven hours’ sleep this last month for two reasons:  overwork (I have an exceptionally heavy workload and it will take at least another three months until this abates…) and my children’s two-week school vacation. With more work to do in less time, I have been playing catch-up at night.

I have, however, managed to push my bedtime forward slightly from 1 or 2 a.m. closer to midnight, and the extra 1-2 hours’ sleep have already made a noticeable difference. I have noticed, for instance, that I drink less coffee (1 cup a day instead of 2-3) and have fewer starch- and sugar-cravings. I have also felt a little more mentally organized which I attribute to the mind-soothing effects of sleep.

Alas, I have been waking up quite frequently in the early morning hours to do a spot of nocturnal pondering (mostly work-related). Over the next month, I will try to get a better handle on managing my thoughts and to-do lists during daytime hours to give my mind a break at night (see this post).

3.    Diet

As I haven’t yet published my Anti-Cancer Diet Plan there’s little to report on this front. However, I have been enjoying daily doses of delicious spring vegetables (crisp asparagus, squeaky spring onions, spicy young carrots, tender spinach, pungent garlic shoots) these last two weeks which has felt invigorating and cleansing. I love coming out of winter and eating fresh spring greens; to me, their emergence from the wintry soil symbolizes hope, vigor and resilience.

More details about anti-cancer eating will feature in my Anti-Cancer Challenge Diet Plan, which I will unveil later this week.

My Anti-Cancer Sleep Plan (I'm yawning already...!)

As I sit here at 11.37 p.m., writing, nibbling on a square of dark chocolate and enjoying the peace and quiet of my hushed home, I know that getting regular, restorative sleep will be a formidable challenge for me - harder than exercising daily or eating healthily. Yet, only this morning, when I awoke grumpy and bleary-eyed after yet another late-night work session, I swore that something had to change, and fast.

Having spent the last few posts discussing the importance of sleep for cancer-prevention, it’s about time I stopped talking and started acting! So here’s my Sleep Plan for the remainder of the Anti-Cancer Challenge (330 days to go):  

• I will sleep for seven hours each night. That seems realistic, and is “only” two more hours than I usually accord myself – I should be able to squeeze those out of my busy schedule!  If I still feel groggy on seven hours’ sleep, I will try to extend my sleep duration.
• To make sure that I actually get these seven hours, I will count backwards from my planned wake-up time; thus, if the alarm is set for 6.25 a.m. (my usual weekday wake-up time), I have to switch off my light at 11.30 p.m. (Actually, that doesn’t sound quite as draconian as I had feared!)
• I will give myself 60 minutes’ winding-down time before lights-out. This may include reading in bed for half an hour – nothing work-related, but instead, relaxing fiction or poetry to help me “get out of my head”.
• Some of that winding-down time may also be spent jotting down any items on my “small stuff” list so they don’t keep me up during the night.
• I keep a Sleep Journal for the first few weeks to help me keep track of my sleep hygiene until my new betimes become a habit.
• I will not check emails after dinner (last week an annoying email that arrived at 11 pm kept me up most of the night!); I can read or shop on-line when the kids are in bed, but I commit to switching off my computer at 10.30 p.m. at the latest.  
• I will go straight to bed when I feel tired. Often, when I start to yawn of feel heavy-lidded, I override my body’s cues and push through the fatigue (frequently with the help of chocolate and bread…), making it doubly hard to get to sleep later. 
• I will spend 30-60 minutes daily under open skies and exposed to unfiltered daylight to stimulate adequate melatonin secretion at night (see this post). Outdoors activities such as gardening, exercising, playing with my kids or sitting on the terrace doing nothing (gasp!!) will feature more often in my otherwise house- and car-bound life.  
• I will exercise daily. I don't know whether these is scientific proof that exercise promotes sleep, but I have noticed that it helps reduce my stress levels and shouldern tension, which may make me feel more relaxed when it’s time to go to bed.
• I will avoid heavy meals in the evening, and when I drink wine, I will limit it to one glass (alcohol consumed before bedtime can distrupt sleep). 
• I keep potentially sleep-disrupting stimulants and sugar to a minimum (no coffee after lunch).
• If I am about to “fall off the wagon”, I remind myself that regular sleep allows me to be a happier, healthier woman with fewer wrinkles and stable weight, a more patient, energetic and resourceful mother and a congruent health practitioner who practices what she preaches.
• And if I do stray occasionally, I won't lose sleep over it. Slips happen.

There – that should get me started! I'd love to hear how some of you make sure that you get the sleep you need - any suggestions?

Next week I will unveil my anti-cancer eating plan, the third cornerstone of the Anti-Cancer Challenge. Meanwhile, have a restful weekend!

Lie back and think of -- nothing!

When I go to bed at night I switch off my light, lower my head on my pillow and wait for Morpheus to cradle me in his sweet embrace. (No, not my husband – this is Morpheus, the Greek god of dreams.)

But while my body is willing, my head won’t follow. For as soon as I want to let go of the day’s cares, I am assailed by half-finished thoughts and an army of to-do-list items marching through my weary mind.

First, I pass review of the Small Stuff: for instance, rescheduling the cat’s vet appointment. This reminds me that I have to make a doctor’s appointment for my son. And book dental check-ups for the twins. Since I’m on appointments, I make a mental note to confirm a birthday-party invitation for my daughter, which in turn reminds me that I have to buy a birthday present for her little friend. Oh, and order that DVD my older son wants for his birthday. For the next five minutes I reel off a list of dozens of things I need to do in the next few days. I grow increasingly tense wondering whether I’ll be able to remember them all by the time the alarm rings the next morning.

This leads on to Medium Stuff: my book that awaits publication, blog posts requiring writing, cooking classes demanding preparation, recipes that want testing, tax declarations, work and family administrivia (and not-so-trivia) that are running late. By now, I’m feeling downright anxious.

From here, it doesn’t take a big step to get to the Big Stuff: the state of the economy, my children’s future, my ageing parents, climate change, and eventually – inevitably – Life, Death and Forgiveness. The script is depressingly familiar, and yet each time it fills me with fear and loathing.

At this point, sleep has become an entirely unrealistic proposition. I get up, pad downstairs and read a boring book to lull myself to sleep. This can take up to an hour. The next morning I’m so tired I feel I need a coffee just to find the coffee!

I have one or two nights like this each week; either my thoughts prevent me from getting to sleep in the first place, or I awake in the middle of the night and the unrelenting cycle of nocturnal ponderings begins anew.

I don’t consider myself to be a particularly tormented soul; it’s mostly a function of having a very busy life and not sorting out my mental clutter before I go to bed. As part of my sleep challenge, therefore, I want to find ways of calming my pointless night-time chatter. Because, let’s face it, night-time ruminations aren’t Quality Thinking Time: I rarely get any real problem-solving or creative thinking done, and in the bright light of day many of the concerns that kept me up at night seem ridiculously small and perfectly manageable. So here’s what I’ll do.

Small Stuff first: I will keep a note pad next to my bed, and before settling in for the night, I will write down any niggling concerns that I haven’t been able to attend to during the day. When I can think of no more items to add to my list, I tell myself: “That’s all for today. You can stop thinking now.”

Medium Stuff: I will keep a comprehensive list on my computer (Microsoft Outlook has a to-do-list-function that includes deadlines and reminders) of the important and/or urgent jobs that need doing and consult it every morning when I begin work, aiming to deal with at least two items before attending to anything else. (I already do this – kind of. For while I often add items to my list, I rarely get around to doing them – just writing them down feels like they’ve been taken care of...)

Big Stuff: this is the most complex nighttime cogitation-fodder, and that which has no Easy Answers. Here’s where taking quiet time to think – and to “not-think” (i.e. meditate) – may help bring some peace.

Talking to loved ones about unresolved conflicts or worries is also important – something I keep putting off, but that keeps coming back to haunt me. So I will schedule time to talk with them, trying to say what needs to be said in the hope of bringing greater clarity and peace to our relationship and to my frazzled mind. And in case my approaches fall on deaf ears, learning to accept things I can’t change and not dwelling on them also strikes me as useful.

Liberating snatches of Quiet Time during the day to “let dangle the soul” (“die Seele baumeln lassen”), as German writer Kurt Tucholsky put it so evocatively, will be a challenge. But my mind has a way of getting what it needs, and if I don’t give it time during the day, it will steal it from me at night.

Turns out (as usual) I was trying too hard

I am the sort of person who tries too hard, and for many years this has been undermining my health and happiness.

When I cook, I strive for the perfect meal. When I write, I want the ultimate piece of prose. When I speak a foreign language, I seek flawless pronunciation. And when I exercise, I expect high performance and constant improvement.

See how I set myself up for failure?  Because, being human, I often don't meet my objectives. And so when I burn the cabbage-and-carrot stir fry, as I did last night, write a less-than-riveting blog post or mispronounce a word in French, I feel bad and put myself under pressure to do better next time.

A case in point is exercise. For many years I have made sporadic attempts to get fit. Since jogging seemed a cheap and universally popular form of exercise, I made several attempts at learning to like it. I would don my running shoes and pound some pavement, but invariably, within 10 minutes or so, I would start to suffer stitches, aching joints and pant like an exhausted greyhound.

Immediately I would be assailed by negative messages from deep down inside: “You’re hopelessly out of shape, you’re weak-willed and at this rate you’ll never get fit, slim and healthy!” I would limp home dejected and eat a butter croissant to make myself feel better. It would take at least a week before I could muster the courage to try exercise again, this time choosing a “safer” option like swimming or cycling (avoiding all elevations).

Now that I have vowed to exercise daily as part of the Anti-Cancer Challenge, and in fresh air when the weather permits, jogging once again has become an obvious choice; but as I contemplated my running route this morning, I felt the familiar dread of not being up to the task. So I decided to take a new approach to jogging by using my heart beat monitor for guidance.

Bearing in mind that my target range for “vigorous exercise” is 130 to 140 heartbeats per minute (bpm), I decided to keep within those parameters. Amazingly, it was one of the most enjoyable workouts I have ever had! Want to know why? It’s simple: all these years I had been running too fast and pushing myself too hard!

When I left the house, the heart rate monitor indicated about 85 bpm. A few minutes’ brisk walking raised it to 120 bpm, and after a few minutes of steady, comfortable shuffling, I was at 145 bpm – and it felt perfectly comfortable!

Granted, the fact that a modest exertion pushed my heart rate to 145 bpm suggests I’m not terribly fit. But the point is, running any faster would have pushed my heart rate well above my target zone, i.e. well above my comfort (and possibly safety) level!

So looking back, I realize I had always been jogging too fast, which had the undesired effect of making me feel more exhausted and demoralized than if I had just stuck to a realistic performance target and actually enjoyed myself!  For – who would have thought! – this morning’s run was such a positive experience, it left me wanting more!

How do my heart monitor’s teachings translate into the other domains of my life? Perhaps it’s telling me I should aim for more realistic results, rendering me less vulnerable to disappointment and allowing me to derive more joy from cooking, writing and speaking French. Sometimes, less is more.

Keeping track of lost snooze-time

As regular readers of the Anti-Cancer Challenge know, I am planning to get more, and better-quality, sleep during the next year (and beyond, hopefully).

I have been feeling decidedly groggy these last few months due to working late, or tossing and turning in bed because I hadn't given myself time to wind down before bedtime. And upon researching the subject of sleep I have become increasingly aware that that insufficient or disrupted sleep may increase our risk of disease: not only cancer (see this recent post), but also diabetes, heart disease, a weakened immune system, inflammation and weight gain.

Fatigue can even kill: driving while tired has similar effects to being drunk at the wheel. The American Academy of Sleep Medicine estimates that one in every five serious motor vehicle injuries is related to driver fatigue, with 80,000 drivers falling asleep behind the wheel every day and 250,000 accidents every year related to sleep. 

Not surprisingly, sleep is also vital for our emotional well-being; conversely, sleep deprivation is thought to increase the risk of depression, stress and anxiety and exacerbate pre-existing mental illness. I certainly have noticed that I relate more easily and joyfully with the people around me when I have slept enough: I am less easily irritated, more patient and altogether more positively inclined toward my fellow-beings.

However, in our fast-paced world it is often hard to get sufficient sleep. Some of us work late into the night (that would include me), others while away the hours surfing the internet to shop, book holidays or catch up on their reading (ditto), and others again seek entertainment from movies or video games which are so stimulating they then find it hard to wind down and get to sleep.

However, many of us are not aware that we're not getting enough sleep. We think being tired and craving coffee and starchy foods - especially in the afternoon - is a normal fact of modern life. And those of us who do realize we should sleep more often don't know where and how to carve out the extra snooze-time.

In order to chart my sleep behavior and find out where I can make improvements, I have designed a weekly Sleep Journal. Those of you joining me on the Anti-Cancer Challenge and seeking to improve your sleep can print it off here. 

You may think I am obsessed with charting. Admittedly, the Sleep Journal comes hard on the heels of the Fitness Diary and heralds the advent of - you guessed it! - the Food Log!  In the arena of weight-loss, however, journaling has been shown to be effective in helping people shed pounds, and so I have decided to apply the same logic to sleep-loss, or rather, gain!

Before we can change our behavior, we need to know first of all what exactly our behavior is! Once we understand where and why we waste precious sleep time (maybe it's not always as important as it seemed at the time?) and discover what our optimal sleep duration is (some of us need more than others), we can leave the journal behind. But for the next few weeks, this document will be my faithful companion!

Sleep: the missing link?

When I launched the Anti-Cancer Challenge I had an intuitive sense that it should include regular, restorative sleep, even though it's not a risk factor many people associate with cancer.

For one, my body has begun telling me that it isn't too happy with my irregular sleep patterns. It's not just that I feel a little tired during the day - that, I can live with. But I have noticed that I'm more prone to colds and infections during prolonged periods of sleep deprivation - when working night after night to meet a deadline, say - than when I'm getting  7+ hours of sleep a night.

Moreover, when I'm missing out on sleep repeatedly, my menstrual cycle shortens and I experience more noticeable PMS symptoms. At first I put this down to approaching menopause, but then I noticed that whenever I managed to sleep more regularly, my cycle would revert to its previous clockwork regularity.

Talking with the people around me, I gather that quite a few of us struggle to get restorative sleep. In many cases, the problem may lie with too muc exposure to artificial light, both at night and during the day.

Prior to the industrial era, humans were exposed to bright, full-spectrum sunlight during the day and to complete darkness at night, and their body clocks closely matched this natural cycle. Since the advent of electric light some 120 years ago, however, our exposure to natural light has been significantly replaced by artificial lighting. Moreover, westernized societies are 24/7 communities where many of us are being exposed to artificial light during the night both at home and particularly in the workplace, thus disrupting our natural circadian rhythms.

Exposure to light at night interferes with melatonin, a hormone involved in a multitude of bodily processes including cardiovascular function, bone metabolism, hormone balance and cancer development and growth. Melatonin is produced in the pineal gland at night, when it's completely dark. When we are exposed to light at night, however, melatonin production is suppressed and this in turn may increase cancer risk though a variety of complex mechanisms.

Studies have shown that melatonin inhibits the development and growth of experimental models of breast cancer, whereas exposure to constant light stimulates mammary tumors in laboratory animals. Epidemiological studies back this up; they show that women working night shifts have a significantly elevated risk of breast, endometrial and colorectal cancer, while male night-shift workers are at a significantly increased risk of developing prostate cancer, presumably due to their increased exposure to light at night. (Read this excellent review for more details.)

Highlighting the seriousness of the problem, the World Health Organization's International Agency for Research on Cancer (IARC) concluded in 2007 that "shift work that involves circadian disruption is probably carcinogenic to humans."

But it's not just night-time exposure to light that's a problem. As a reader of my Psychology Today blog "Nourish" helpfully pointed out, nocturnal melatonin production is also strongly influenced by how much daylight we are exposed to. A Japanese study found that spending one's day in dim indoor lighting leads to a weaker increase in melatonin levels at night than being exposed to bright outdoor sunlight. Thus not only shift-workers, but anyone leading an indoor and in-car lifestyle, like me, may be affected.

On the other hand, sleep duration - number of hours slept - is less clearly linked to cancer risk; indeed, epidemiological investigations have yielded ccnflicting results. While a Finnish study indicated that women sleeping 9 hours a night or longer were 31% less likely to develop breast cancer than women reporting 7-8 hours of sleep per night, a British study found no significant difference in the breast cancer risk of those sleeping 9 hours or more and those getting less sleep, and a third study actually detected a small increase in the breast cancer risk among women reporting more than 9 hours of sleep.

Conventional wisdom holds that 8 hours of sleep are "normally" required for optimal rest, but not all experts agree. "The fixation on sleep duration is unhelpful," comments Kevin Morgan, Professor of Gerontology at Loughborough University. "Sleep needs vary enormously from one person to another." As he sees it, the best criterion to measure sufficient sleep is "whether we feel restored by our sleep and are able to do what we need to do throughout the day." Age and gender also influence how much sleep we need, he says, making it impossible to set a "correct" number of hours people should sleep each night.

So where does all this leave people like me, who are not exactly shift workers but do spend a large portion of their nocturnal hours bathed in artificial light? David Blask of the Tulane University School of Medicine, New Orleans, speculates that non-shift working individuals who are not melatonin-deficient but who are chronically sleep-disturbed or deprived for other reasons may be at greater risk of developing cancer "due to the independent effects of immune suppression induced by sleep deprivation," though he notes that this hypothesis needs to be tested through more research.

What does this mean for my sleep challenge? I am still piecing together the puzzle, but initial conclusions are emerging. One is that sleep disruption and night-time work may have a negative effect on my immune system and overall hormone balance - as witnessed by the symptoms described above. In addition, daytime exposure to full-spectrum light is something I should increase from current near-inexistent levels. (Lighter, warmer spring and summer weather should help.)  I don't plan to sunbathe - another cancer risk! - but exercising outdoors rather than in my living room would be a good place to start.

Moreover, sleeping in a fully darkened bedroom should help stimulate melatonin production. And while sleep duration may not be directly relevant, I will try to increase mine a little for I do not currently meet Professor Morgan's criterion of feeling "restored and able to do what I need to do throughout the day."