I wrote a letter to an acquaintance who had recently suffered a heart attack, about possible dietary interventions. I thought this might prove to be interesting to others, so part of my letter is reproduced here.
From my files on cardiovascular disease I've gathered that getting more
exercise, eating less meat (except fish), and consuming more fruits,
vegetables, nuts and legumes is likely to modestly lower the risk of
cardiovascular fatalities. For a more significant reduction in risk it
seems one has to go beyond the standard recommendations one hears from
A good example of this is from (J Am Col Nutr 1293): 255-261 1993). The mortality rate of patients who had suffered a heart attack was found to vary dramatically with the quantity of fruits and vegetables the patients ate as follows:
Control Dietary Invention Groups "B" A1 A2 Fruit & vegetables (g/day) 182 492 652 Total Mortality 13.8% 10.4% 5.5%
I doubt many doctors would be disatisfied with any patient who was
eating about 492 grams of fruits and vegetables per day! However this is
still a dangerously poor diet, with about double the mortality rate of
those who consumed still more fruits and vegetables.
There is very little data indicating what the optimal quantity of fruits
and vegetables one should consume for maximum longevity, possibly because
virtually nobody ever consumes this. I would recommend maintaining an
intake over 1 kilogram per day to be on the safe side.
There are probably great variations in how protective individual fruits
and vegetables are. For example there exists some data suggesting that
eggplant actually raises blood pressure. However based on the information
at hand I can make two suggestions that I feel stand out from the crowd as
likely more protective than most. One is garlic. It has been found that
taking at least 300 mg/day of garlic powder for over 2 years was
associated with increased elastic properties of aorta in the elderly.
(Circulation 96: 2649-2655 1997) Doses larger than 300 mg were not more
protective so a very modest daily intake of garlic or its powder is my
An interesting study was done relating adipose biopsy carotenoid concentration with risks of a heart attack. This is particularly interesting since tissue concentrations reflect long term intake of carotenoids. Only lycopene had a significant relation with risk, which decreased progressively with higher tissue concentrations. There was no indication of a maximum threshold beyond which lycopene had no further effect. (Am J Epidemiol 146: 618-628 1997) I would like to suggest two easy ways to increase fruit and vegetable intake to over 1 kg/day. I've found that 1 kg of seedless watermelon makes a nice snack - when it is in season. I've tried a variety of tomato products, to see how easy it is to consume them. Raw tomatoes are slightly bitter, and most tomato sauces have an "off" taste. Tomato soup tastes bland. I've found one tomato sauce which tastes very good. The brand is called Bielle, and it is manufactured in Alberta. It contains tomato puree rather than paste, and this might make the difference. I doubt any rotting tomatoes were used to make this sauce. However this is expensive and may be hard to obtain. Based on taste and cost the easiest way I've found to consume large quantities of tomatoes is tomato juice. Lycopene is less easily absorbed from tomato products that are less heat processed, but tomato juice is hard to beat if large amounts are to be consumed. Consumption of 330 ml/day of tomato juice has been found to reduce DNA damage in lymphocytes. (Carcinogenesis 18(9): 1847-1850 1997) (The same study also found carrot juice to be even more effective.) You might want to consider purchasing a juicing machine. When increasing fruit and vegetable intake, it is important to avoid flatulence inducing ones! Many vegetables suffer from this side effect, so concentrating on fruits more than vegetables would likely be the easier route. (The only legume source free from this side effect seems to be processed soybean products such as tofu, and soy milk.) I should mention that some vegetables are also associated with increased risk of side effects, such as stone formation with oxalate rich spinach, and sun burn with psoralen rich celery.
A funny thing happened during the Adventist Health Study relating diet to mortality, in a group with one seventh the heart attack risk of the general population, and who already live 7 years longer. The big finding was the largely unsuspected health benefits of nuts. Here's some data from (Arch Intern Med 152: 1416-1424 1992).
Relative Risk Food Item frequency of Fatal CHD nuts <1/wk 1 1-4/wk 0.77
legumes <1/wk 1 1-2/wk 0.98
fruits <1/d 1 1-2/d 1.17
beef never 1 <3/wk 1.12 >=3/wk 1.19
This nut/longevity relation was later found to hold even in old age. Here's some data from those over 84 years of age. (Arch Intern Med 157: 2249-2258 1997)
nuts <1/wk 1 1-4/wk 0.71 >4/wk 0.55
I've looked at the data comparing the effects on lipids of various types of nuts. The best results seem to be with almond ingestion, which results in a better HDL/LDL ratio than with olive oil. (J Am Col Nutr 17(3): 285-290 1998) It's probably a good idea to consume some nuts on a regular basis - particularly almonds.