Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study
BMJ 1998; 317 doi: https://doi.org/10.1136/bmj.317.7169.1341 (Published 14 November 1998) Cite this as: BMJ 1998;317:1341All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Editor,
It is encouraging to read that frequent consumption of nuts,
including peanuts, may reduce the risk of coronary heart disease in the
United States1. We wonder whether the same would hold true in Britain? Our
observation suggests that the majority of nuts consumed here are salted.
Several researchers have convincingly demonstrated the link between salt,
hypertension2-4 and therefore coronary heart disease5.
Yours faithfully
Daniel Jones
Senior House Officer
Tim Heymann
Consultant Physician
Department of Medicine
Kingston Hospital
Kingston Upon Thames
SURREY KT2 7QB
1 Hu F, Stampfer M, Manson J, Rimm E, Colditz G, Rosner B, Speizer
F, Hennekens C, Willett W. Frequent nut consumption and risk of coronary
heart disease in women: prospective cohort study. BMJ 1998 317 1341-5
2 Stamler J, Rose G, Stamler R, Elliot P, Dyer A, Marmot M.
INTERSALT study findings: Public health and medical care implications.
Hypertension 1989 14 570-77
3 MacGregor GA. Salt - Overwelming evidence but still no action: can
a concensus be reached with the food industry? BMJ 1996 312 1287-9
4 Cappuccio FP, Marhadu ND, Carney C, Sagnella GA, MacGregor GA.
Double blind randomised trial of modest salt restriction in older people.
Lancet 1997 350 850-4
5 Sleight P. Primary prevention of coronary heart disease in
hypertension. J Hypertens Suppl 1996 14 S35-9
Competing interests: No competing interests
Editor – The article by Hu et al. about frequent nut consumption and
risk of coronary heart disease in women (1) concludes that frequent nut
consumption reduces the risk of heart disease significantly. In their
discussion the authors suggest several mechanisms through which the eating
of nuts might have this effect. Unfortunately they forget to mention why
people eat nuts and how this affects their diet.
My hypothesis would be that most people eat nuts as a snack. This
"healthy" snack replaces other commonly less healthy snacks like a
chocolate bar or sweet biscuits. It could well be that the reduced
consumption of refined sugars and not the additional intake of "healthy"
ingredients from nuts is the key to the reduced risk of CVD found. This
conclusion is supported by the work of TL Cleave (2). Despite Hu's
attention to dietary variables information about refined sugar intake is
missing. So is information about triglyceride levels which could have
provided an indirect indicator of sugar consumption.
Frank Teunisse, General Practitioner.
Benoran, Isle of Colonsay, Argyll PA61 7YW
1 Hu F, Stampfer M, Manson J, Rimm E, Colditz G, Rosner B, Speizer F,
Hennekens C, Willet W. Frequent nut consumption and risk of coronary heart
disease in women: prospective cohort study. BMJ 1998; 317: 1341 – 1345 (14
November)
2 Cleave TL The saccharine disease. Bristol: John Wright and sons Ltd.,
1974
Competing interests: No competing interests
Once again, interesting study, but PLEASE stop using relative risks
to present data! Was the hypothesis stated a priore, or was this another
data dredging post hoc analysis? The absolute risks and risk reductions
in this trial are EXTREMELY small and likely insignificant, especially
after the confounding variables are taken into account, and especially
when considering that the relative risk confidence intervals are always
either very close to or crossing 1.00! I would however like to see a
delicious prospective trial. I would also like to see an MMSE done on all
patients in the prospective trial. The title could then be "Are nuts
useful in nuts?"
I am somewhat reassured, however, being a real nut addict, that it
hasn't yet been proven that nuts will do any major harm to me...
YS
Competing interests: No competing interests
Areca: The not so healthy nut
EDITOR -
The editorial in the BMJ (14 November 1998) by Tunstall-Pedoe
entitled "Nuts to you (… and you, and you)" and the US nurses' study1
report some health benefits in eating several helpings of nuts a week.
These benefits cannot be generalised to all nuts commonly consumed and it
is important to specify which nuts produce such health benefits. The areca
nut (erroneously referred to as the betel nut) is chewed by over 200
million people world wide – a tenth of the world population. It is either
chewed alone or as a part of a quid known as ‘pan'. This habit is
practised commonly in central, southern and south-east Asia and is now
also emerging in the Western countries. Recently new information on
medical, biochemical and psychological correlates of areca nut use have
been reported.2 Several deleterious effects on oral and general health
are now linked to areca use. The consumption of areca has been strongly
linked to the development of oral submucous fibrosis (OSF) – a potentially
malignant disorder of the oral cavity3 and a high incidence of oral cancer
in the Indian subcontinent and among Indian immigrants. Areca consumption
has also been linked with cardiovascular responses,4 diabetes5 and asthma.
6 We have recently described an areca dependency syndrome in a group of
Indian (Gujarati) immigrants living in west London who were addicted to
areca products.2 A high proportion (8/11) had some form of cardiovascular
disease, two were diabetic and 4/11 had low serum B12 levels. Larger
epidemiological studies from south-east Asia have reported micronutrient
deficiencies in heavy areca chewers.
The mechanisms by which areca may induce cardiovascular disease are
not clearly understood. A recent study on a Bangladeshi population in
east London found raised homocysteine levels and reduced folate levels in
170 healthy regular chewers.7 High serum homocysteine has been associated
with an increased risk of acute ischaemic heart disease. It was
interesting to note that the investigators found a positive correlation
between the total homocysteine concentration and the frequency of
consumption of areca products. Another possible mechanism involves the
copper-dependent enzyme lysyl oxidase (LO) involved in the cross-linking
of collagen and atherogenesis in the major vessels.8 We have shown in
previous studies that areca contains a high level of copper 302 (± 92)
nmol/g (range 205-535 ) compared to other nut-based snacks (range 22-173
nmol/g).9 Dietary copper is known to influence lysyl oxidase activity and
we have demonstrated raised copper and lysyl oxidase levels in the oral
mucosa of patients with OSF who were all heavy areca chewers.10
It is therefore feasible to propose that areca via the lysyl oxidase
pathway or through raised homocysteine may contribute to the development
of ischaemic heart disease in heavy areca chewers. Further studies to
assess the role of areca chewing in asthma are in progress.
As shown in the US study eating nuts may be a safe and healthy habit
but recommendations encouraging frequent consumption should specify safe
nuts and consider deleterious effects of some nuts such as areca.
Chetan Trivedy
Research fellow
Saman Warnakulasuriya
Senior Lecturer Oral Medicine
Timothy J Peters
Professor of Clinical Biochemistry
King's College Hospital
London SE5 9RW
1 Hu FB, Stampfer MJ, Manson JE. et al. Frequent nut consumption and
risk of coronary heart disease in women: prospective cohort study. BMJ
1998; 317: 1341-5.
2 Trivedy CR, Winstock AR, , Warnakulasuriya KAAS, Sherwood RA,
Peters TJ.. Areca nut product usage: A previously unrecognised dependency
syndrome (abstract). Addiction Biology 1999 (in press).
3 Warnakulasuriya KAAS, Trivedy C, Maher R, Johnson NW. Aetiology of
oral submucous fibrosis. Oral Dis 1997; 3: 286-7.
4 Chu NS. Cardiovascular responses to betel chewing. J Formos Med
Assoc 1993; 92: 835-7.
5 Boucher BJ, Ewen SWB, Stowers JM. Betel nut (Areca catechu)
consumption and the induction of glucose intolerance in adult CD1 mice and
in their F1 and F2 offspring. Diabetologia 1994; 37: 49-55.
6 Taylor RFH, Al-Jarad N, John LME, Conroy DM, Barnes NC. Betel-nut
chewing and asthma. Lancet 1992; 339: 1134-36.
7 Obeid OA, Mannan N, Perry G et al. Homocysteine and folate in
healthy east London Bangladeshis. Lancet 1998; 352: 1829-1830.
8 Kagan HM, Raghavan J, Hollander W. Changes in the aortic lysyl
oxidase activity in diet-induced atherosclerosis in the rabbit.
Atherosclerosis 1981; 1: 287-29.
9 Trivedy C, Baldwin D, Warnakulasuriya KAAS, Johnson NW, Peters TJ.
Copper content in areca catechu (betel nut) products and oral submucous
fibrosis. Lancet 1997; 340: 1447.
10 Trivedy C, Warnakulasuriya KAAS, Hazarey VK, Tavassoli M, Sommer
P, Johnson NW. The immunohistochemical localisation of lysyl oxidase in
oral submucous fibrosis and squamous cell carcinoma. J Oral Pathol Med
1999 (in press).
Competing interests: No competing interests