DNC News:  Out of whack meal times increase cancer risk
Jacob Schor, ND, FABNO
August 16, 2018

A new study by Kogevinas et al touches on that old theme of early to bed and early to rise, but not exactly.  It does provide another piece of information to an increasingly complex puzzle of how lifestyle and our prehistoric biology interact and perhaps inform us of what might be a healthier way to live.
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Up to now when we’ve talked about diet and risk of cancer, we’ve thought in terms of other dietary constituents or specific foods.      We’ve reviewed articles on carbohydrate intake and breast cancer recurrence risk.  We’ve reviewed the lack of evidence that fat intake changes breast cancer risk.      We’ve looked at associations between specific foods and specific cancers such s eggs and prostate and olive oil and breast cancer.  This study looks at when we eat and when we sleep and suggests that these choices may have a larger than previously thought impact.

A few years back we reviewed Carol Marinac and Ruth Patterson’s papers that suggest longer night time fasting reduces breast cancer recurrence risk.    This new paper, though looking at a different set of parameters, kind of fits in the same file folder. Kogevinas et al looked at when the evening meal is eaten and how long after the person goes to sleep.  Put simply, the earlier people eat and the longer they wait until they go to sleep, the better, though it is more complicated than that.

This was a population-based case-control study using data gathered in Spain from 2008-2013.  We should note immediately that the cultural norm in Spain is to eat late in the evening and we cannot apply this data easily to Americans.  The data came from MCC-Spain, a population‐based case‐control study that includes cases from five tumor types and population controls conducted in 12 regions of Spain in 2008–2013.  This study’s analysis included 1,738 breast and 1,112 prostate cancer cases aged 20–85 who were histologically confirmed. Individuals who had ever worked night shifts were then excluded from the group leaving 621 cases of prostate and 1,205 of breast cancer and 872 male and 1,321 female population controls who were randomly selected from primary health centers and were frequency matched by sex, geographical area and age.  The subjects were interviewed on timing of meals, sleep and chronotype and completed a Food Frequency Questionnaire.

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Compared with subjects going to sleep immediately or shortly after supper, people who delayed going to sleep for two or more hours after supper had a 20% reduction in cancer risk for breast and prostate cancer combined (adjusted Odds Ratio [OR] = 0.80, 95%CI 0.67-0.96) and in each cancer individually (prostate cancer OR = 0.74, 0.55-0.99; breast cancer OR = 0.84, 0.67-1.06). A similar protection was observed in subjects having supper before 9 pm compared with those eating their evening meal after 10 pm. The effect of a longer supper-to-sleep interval was more pronounced among subjects adhering to other cancer prevention recommendations (OR both cancers= 0.65, 0.44-0.97) and in morning types (OR both cancers = 0.66, 0.49-0.90).  Subjects having both earlier supper (before 9 pm) and longer interval between supper and sleep (>2 hours) had an approximately 25% decreased combined cancer risk (OR = 0.76, 0.57–1.0) compared with those having supper after 10 pm
supper‐sleep interval.

Adherence to diurnal eating patterns and specifically a long interval between last meal and sleep were associated with a lower cancer risk, stressing the importance of evaluating timing in studies on diet and cancer.

Before and since then, experimental and epidemiological data have associated chronic circadian disruption with a number of chronic diseases as well including diabetes, obesity, cardiovascular disease and others.       [3,4,5]

Clearly there is something about regular patterns of sleeping that affects health. A June 2018 paper which proteins are altered when meals are eaten out of synch to the internal circadian clock.  Of 1,129 proteins analyzed, about half (573) fluctuated during a 24-hour circadian cycle.  “Circadian misalignment altered 127 of these proteins.  These altered pathways were involved in immune function, metabolism and cancer.  [6] This study suggests timing of meals may also have an effect.

Experimental and epidemiological evidence shows that long term disruption of endogenous circadian rhythms, in particular due to exposure to light at night, may be associated with a wide
range of common diseases, including cancer, cardio vascular diseases, obesity and type 2 diabetes.

Most studies on nutrition and cancer have focused on types of food consumed rather than meal timing, either macromolecules or specific foods containing phytonutrients of interest.  A still small number of studies have examined eating patterns.  In an earlier review, this author described Marinac’s studies that suggest longer night time fasting is associated with lower risk of breast cancer recurrence.

This current paper adds several new ideas to our understanding that could have clinical relevance.

First, going to sleep immediately after eating the evening meal is associated with an increased risk of breast or prostate cancer.  Delaying sleep just two hours lowers the combined risk for either of these cancers by a fifth or 26% for prostate and 16% for breast cancer.   Ascertaining which of our patients are in the habit of going to bed too early and getting them to change this habit might lead to lower cancer risk.  The choice would be an earlier dinner or a later bedtime.  Given Marinac’s results an earlier dinner might be more advantageous. [link to our Marinac review: https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.naturalmedicinejournal.com%2Fjournal%2F2016-09%2Fnightly-fasting-improves-breast-cancer-prognosis&data=02%7C01%7C%7Cc47b3c2d14af4d71ffa908d603a8f277%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636700421482540921&sdata=sq9B6YsOfpi8U3aOzXgpiZKShOYVNuXrBTdLlHuq9Wg%3D&reserved=0  ]

Second, eating the evening meal early may also lower cancer risk.  We must remember that these data are from Spain where the cultural norm is to delay the evening meal to relatively late at night by American standards.  In this study, eating supper before 9 pm was associated with an approximately 35% lower risk of cancer compared to eating after 10 pm. How this will translate into the U.S. population that generally eats supper around 6 pm is unclear.

Combining both practices, eating early and delaying going to sleep for a few hours after eatin may be the best idea.

Third, the impact of meal timing varies by certain general characteristics.  The data in this study were further analyzed by the person’s chronotype, a concept that is recently getting attention.  The study authors describe chronotype as “… a human attribute with genetic basis that correlates with diurnal preference for activities in the morning or evening.”  In simpler words whether the individuals were better described as ‘night owls’ or ‘early birds’.  The protective benefits of meal times and sleep patterns was greater for chronotypes that favored morning activity, a 34% risk reduction of cancer risk for the morning types compared to only 14% reduction in the night types.  Meal and sleep timing makes a larger difference in early birds than in night owls.

This study gives support to a number of traditional naturopathic concepts, in particular eating early.  It also suggests that simple interventions and changes in lifestyle may have significant impact on cancer risk.

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1.  Full text: https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2Fepdf%2F10.1002%2Fijc.31649&data=02%7C01%7C%7Cc47b3c2d14af4d71ffa908d603a8f277%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636700421482540921&sdata=vFMiD04x1ulEUF3RLb5PQ8yjzfouWXiBkoXa1a6kZJA%3D&reserved=0
Kogevinas M, Espinosa A, Castelló A, et al. Effect of mistimed eating patterns on breast and prostate cancer risk (MCC-Spain Study). Int J Cancer. 2018 Jul 17.

2.  https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.iarc.fr%2Fen%2Fmedia-centre%2Fpr%2F2007%2Fpr180.html&data=02%7C01%7C%7Cc47b3c2d14af4d71ffa908d603a8f277%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636700421482540921&sdata=Mwv9KtRMBfBq3rjdITZZfkK9buYMtLvnkZUJVd1B1HQ%3D&reserved=0

3.  Adverse metabolic and cardiovascular consequences of circadian misalignment. Scheer FA, Hilton MF
CS Mantzoros, SA Shea – SLEEP MEDICINE

4.  Machado RM, Koike MK. Circadian rhythm, sleep pattern, and metabolic consequences: an overview on cardiovascular risk factors. Horm Mol Biol Clin Investig. 2014 Apr;18(1):47-52.

5.  Leproult R, Holmbäck U, Van Cauter E. Circadian misalignment augments markers of insulin resistance and inflammation, independently of sleep loss. Diabetes. 2014 Jun;63(6):1860-9.

6.  Depner CM, Melanson EL, McHill AW, Wright KP Jr. Mistimed food intake and sleep alters 24-hour time-of-day patterns of the human plasma proteome. Proc Natl Acad Sci U S A. 2018 Jun 5;115(23):E5390-E5399.

7.  Roenneberg T, Kuehnle T, Juda M, et al. Epidemiology of the human circadian clock. Sleep Med Rev 2007;11:429–38.