Diet as placebo? Why not?
By Robert Teed
Published: October 21 2006 03:00 | Last updated: October 21 2006 03:00
We are bombarded these days with advice on healthy eating. The government, in line with international guidelines, repeatedly encourages us to eat five decent-sized portions of fruit and vegetables a day. Sadly, the ginger in ginger nuts doesn't count.
It is an uphill struggle. Changing people's behaviour nearly always is. But sometimes, we can change our behaviour radically if we believe strongly enough in the reasons for change. Mary Hitchin was diagnosed in autumn 2003 with breast cancer. Subsequently, she went from one pattern of behaviour to another in months, convinced by arguments she read in Jane Plant's book Your Life In Your Hands that linked meat and dairy consumption in western diets with the prevalence of breast cancer. "Someone gave me the book and it made total sense," she recalls.
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At the time, Hitchin was undergoing a harrowing programme of chemotherapy; it seems odd that she should have embarked on such an extreme change to her diet (it meant cutting out all dairy products, red meat, caffeine and alcohol) at such a vulnerable moment in her life. "I don't think of it as extreme or radical," she says, "and it didn't feel sudden, it felt gradual. It was more about increasing the ratio of vegetables to proteins."
Three years after her diagnosis, Hitchin's prognosis is good and she is clear of cancer. Yet she is also, she thinks, eating less healthily.
"My diet sort of dwindled away," she says. "I think as I became more hopeful about my longevity, I was also increasingly saying to myself 'life's too short not to eat chocolate'. Now there are days when I am wise and days when I'm gluttonous."
Professional advice on healthy eating often focuses on the phrase "balanced diet". Professor Hilary J Powers, professor of nutritional biochemistry at the University of Sheffield, believes in general that a good diet is one rich in fruit and vegetables, high in fibre and low in fat. She is also concerned that cutting out meat and dairy products in a diet cuts out essential proteins and minerals - the average person's dairy consumption, for example, can provide up to a third of our daily intake of calcium, Vitamin D and water-soluble vitamins such as Riboflavin, which are difficult to come by in other foods.
There is no scientific evidence linking strange diets to recovery from cancer but Prof Powers believes Hitchin may have derived some sense of well-being from her diet simply because in cutting out dairy and red meat one reduces significantly one's calorie intake. The diet may have acted as a placebo, making her feel more in control of her illness and recovery. However, Prof Powers is keen to emphasise that undertaking such a placebo diet at a time of acute illness is unwise, as one runs the risk of depriving the body of key nutrients at a vulnerable period.
Hitchin's diet seems by definition to have been "unbalanced" because it demanded the cutting out of certain food groups. She is not convinced: "I think 'unbalanced' is wrong. If you do these things carefully, then you supplement from other sources. So I used soya milk instead of cows' milk, and cereals and pulses for protein, and Marmite for my Riboflavin. But I admit it was difficult to manage."
Hitchin's diet has waned over time. She feels guilty for not keeping it going; but it may simply be that the need for that diet at that particular time in her life has passed.
抗癌食谱并不科学？
作者：英国《金融时报》 罗伯特?提德(Robert Teed)
2006年11月3日 星期五
近
来，关于健康膳食的建议铺天盖地向我们袭来。政府按照国际标准，反复鼓励我们每天吃5份数量可观的水果和蔬菜。遗憾的是，姜汁饼干中的姜还不算。
这是一场艰苦的斗争。改变人们的行为几乎总是如此。但有时，如果我们对改变的理由深信不疑，我们也可以彻底改变自己的行为。玛丽?哈特金(Mary Hitchin)在2003年秋被确诊患上了乳腺癌。后来，她读了简?普朗特(Jane Plant)的著作《掌握自己的生命》。书中认为，西方饮食中的肉奶消费量与乳腺癌频发之间存在关联。她相信了这种观点，于是在几个月中改变了自己的行为方式。“有人给了我那本书，它讲的非常有道理，”她回忆道。
当时，哈特金正在接受痛苦的化疗；她在生命中一个如此虚弱的时刻如此极端地改变膳食习惯（意味着停止摄取所有奶制品、红肉、咖啡因和酒精），这似乎有些奇怪。“我并不认为这很极端或偏激，”她说道，“而且我感觉它来得并不突然，是一个渐进的过程。这种膳食的关键是提高蔬菜对蛋白质的比例。”
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在确诊三年后，哈特金的预后检查结果良好，她彻底摆脱了癌症。不过她认为，她吃得也没有以前健康了。
“我逐渐不那么严格遵守膳食计划了，”她说道。“随着对自己的寿命越来越乐观，我也在越来越多地告诉自己：‘生命太短暂了，不能不吃巧克力’。现在我有时候能保持克制，有时候却暴饮暴食。”
健康饮食方面的专业建议通常集中在“均衡膳食”这个词上。谢菲尔德大学(University of Sheffield)营养生物化学教授希拉里?J?鲍尔斯(Hilary J Powers)大体上认为，好的膳食应有丰富的水果和蔬菜，高纤维，低脂肪。她也担心，去掉膳食中的肉类和奶制品，会去掉人体必需的蛋白质和矿物质――例如，一般人的奶制品消费量可以提供多达三分之一的钙、维生素D和核黄素等水溶维生素日常摄入量，而这些微量元素难以从其它食物中获取。
目前尚无科学证据表明，特殊膳食与癌症康复之间存在关联，但鲍尔斯教授认为，或许仅仅是因为停止食用奶制品和红肉，会大幅减少一个人的卡路里摄入量，从而使哈特金从膳食中获得了某种健康感。这种膳食或许充当了安慰剂的角色，使她感觉能更好地控制病情和康复。但是，鲍尔斯教授坚定地强调，一个人在病情如此严重的情况下，采取这类安慰剂膳食计划并不明智，因为在虚弱时期，它有可能剥夺人体所需的重要营养。
从均衡膳食的定义上来看，哈特金的膳食似乎并不均衡，因为它要求将某些食物类别排除在外。对此哈特金并不认同：“我认为‘不均衡’的说法是错误的。如果细加安排，你可以从其它来源获取营养。因此，我用豆奶代替牛奶，并通过食用谷物和豌豆来摄取蛋白质，通过酵母酱(Marmite)来摄取核黄素。但我承认，这种膳食很难控制。”
随着时间的推移，哈特金已经不再坚持膳食计划了。她因未能坚持下去而感到遗憾；但这或许仅仅是因为，她生命中那个需要这种膳食的特殊时刻已经过去了。
