Vegetable Type & Quantity Affect the Risk of Coronary Heart Disease

More the Variety, better the Capability to Fight against CHD

As a kid I remember my dad telling me one solution for every health complaint I used to bring to his notice and that was none other than to eat more fruits and vegetables along with my daily diet intake. I had mixed emotions-sometimes I was frustrated, sometimes very angry and at other times I used to just ignore his suggestion but I never had the inclination to never pay heed to his suggestion and work upon it. Growing up, I realized the worthiness of his valuable comments after I started reading health magazines, newspaper articles and started seeing that my friends too who had taken up a produce-rich diet that’s good for wellness and health. Beyond all, the craziness of my adolescent wish to lose weight, become extremely slim and look chic prompted me for such a sudden transition in my eating habits that comprised of a vegetable-enriched diet. Just because fruits and vegetables are always included as a part of our daily cooking routine there isn’t much attention that we give to it! In fact, most of us show a face when served with most vegetables other than few like potato or cauliflower. The nutrient-rich beans, carrots, pears, apples and tomatoes that sit tight in our refrigerators and kitchen cabins are yet to find a place in most of our hearts but not with much success! Maybe, once you realize the goodness and benefits of these produce I am sure that none of us would ever again ignore to start eating them.

Don’t Have a Grudge Against Veggies
Vegetables intake has been insisted upon as it’s a rich source of micronutrients and phytochemicals that help to protect the body against chronic disease and also reduce the risk of death from conditions such as coronary heart disease (CHD) and stroke. A meta-analysis of studies showed that regular consumption of fruits and vegetables (more than 5 portions daily) was linked to a 17% reduced risk of CHD when compared to the consumption of less than 3 portions daily. For every increase in portion of produce intake the risk of CHD decreased by 4% in yet another meta-analysis. But when we look behind the reason for such a variation in risk its seen that the type of fruit and vegetable consumed and also the processing method have a strong role to play in this apart from the cooking method, the type of produce consumed as some veggies and fruits are more beneficial than others, saturated fat intake, lifestyle factors and smoking habits.

The Dietary Guidelines for Americans (DGA) 2015-2020 provides specific recommendations for daily vegetable intake depending on energy needs and also provides specific recommendations for different subgroups including dark green, red, legumes, starchy veggies and other kinds of veggies too. The reason why the DGA recommends different proportions for consumption of different vegetables is because of the simple fact that the health-promoting bioactive compounds are not evenly distributed across all vegetables. Moreover, introducing a variety of vegetables over a meal also has the potential to increase the liking of these vegetables and therefore, the quantity of the vegetables consumed. We have ample studies in our kitty that encourage us to consume more vegetables on a daily basis. Cross-sectional studies show that a higher variety of fruits and vegetables intake was linked to a lower risk of obesity, metabolic syndrome, hypercholesterolemia and hypertension but these studies did not distinguish variety from quantity and we don’t know whether the association for variety was independent of the quantity consumed. Still, there are hardly a few studies that find a strong association between the variety of vegetables consumed and their benefits on heart health. So, it would make sense to take up those studies that deal with a variety of vegetables and their effect on CHD and also examine the association of quantity and variety in produce intake and its relationship with CHD.

Greater the Variety of Produce, Smaller the Risk of CHD
The study elaborated here focuses on the variety of vegetables consumed and their effect on CHD. The Healthy Food Diversity index (this index can be applied to different population groups by making only two small changes-define the food groups to be included and consumption targets for these food groups) was used to measure vegetable variety that’s independent of the total quantity of vegetables consumed. The index is comprised of two parts namely the Berry Index and the Health Value and its value is fetched by multiplying the two parts. The index score is bounded by 0 and 0.64 and higher scores are achieved when there is more consumption of vegetable subgroups and there is greater consumption of vegetable subgroups that have a greater weight.

To assess the relationship between vegetable variety and cardiometabolic disease the participants in the study were categorized by quintile of vegetable variety scores with those in quintile 1 having lowest score and those in quintile 5 having greatest scores. To find the relationship between vegetable amount and each cardiometabolic disease subtype participants were categorized by quintile of vegetable amount (those in quintile 1 had lowest intake amount and those in quintile 5 had greatest intake amount). Also, to understand the link between each vegetable subtype and prevalent disease individuals were categorized as either consumers or non-consumers.
The study included 38, 981 participants in which most of them were between 31 and 50 years of age and 52% were females. Of the total number of participants, 53% did not report smoking status, 53% had a BMI between 25 and 30, mean household size was 3 persons, 63% were living with a domestic partner and 81% reported being fully food secure. Participants consumed a mean of 3.4 meals per week away from home and 7000 respondents were told by a physician that they suffered from cardiometabolic disease. Results showed that:

1. The mean daily vegetable variety score decreased from 0.35 in 2000 to 0.33 in 2014. In this same period the variety of vegetables consumed decreased among men but not women but surprisingly men displayed higher vegetable variety scores
2. Those living with a domestic partner had 22% chances of being in the highest quintile of vegetable variety comparatively
3. Participants who smoked had 14% decreased chances of being in the next highest quintile compared to those who did not smoke
4. Women reported greater consumption of vegetables than men
5. There was a decrease in intake of starchy vegetables while an increase in the intake of dark green vegetables
6. Compared to individuals in quintile 1 there was no relationship observed between greater vegetable intake and disease prevalence but across quintiles it was observed that greater vegetable intake was associated with a lower risk of coronary heart disease.
7. Women showed that those in quintile 5 had lower odds of risk of cardiovascular disease but there was no relationship found between vegetable amount and disease subtype
8. Individuals who reported consuming dark green veggies on the day of the survey had lower risk of cardiovascular disease and coronary heart disease compared to those who reported not consuming any greens.
9. Men who consumed more starchy vegetables were at an increased risk of diabetes but among women, there was no association between vegetable subtypes consumption and disease risk.

The study clearly shows that vegetable variety and amount are inversely associated with prevalent coronary heart disease. Each of the vegetables are rich in different nutrients-dark green veggies are rich sources of nitrates, folate and carotenoids (helps to avoid inflammation and oxidative stress). Spinach, beets and broccoli are rich in phenolic compounds and display antioxidant activity. Also, most of the vegetables are rich sources of potassium that’s essential for blood pressure homeostasis.

Another study happened in a group of Chinese men and women. 67, 211 women aged 40-70 and 55,474 men aged 40-74 involved in the study were assessed of their food intake with a food-frequency questionnaire (FFQ). Frequencies and amount of food intake was converted into daily intake of each food. Total fruits and vegetables intake were derived by summing intake of all the fruits and vegetables consumed during the entire day. The FFQ included fruits such as pear, apple, citrus fruits, watermelon, banana, peach and grapes among other fruits while there were 33 vegetables including cruciferous vegetables, alliums, legumes and other vegetables such as celery, eggplant, cucumber, tomato, sweet potato and bean sprouts. Results showed that total fruits and vegetables intake was 502 g/d among women and 440 g/d among men. Women generally consumed more fruits and less vegetables compared to men. It was also observed that those who consumed more produce had higher income, education and were likelier to use more supplements. Women in the highest quartile of total fruit and vegetable intake had a hazard rate (HR) of 0.62 for CHD compared to those in the lowest quartile. For every increase in portion intake of produce there was a 6% reduction in CHD incidence among women and also the HR for CHD decreased with every portion increment in fruit and vegetable intake. In case of men, the lowest HR for CHD occurred at 6 portions per day. It was only banana that stood apart from the rest of the produce-a higher banana intake was associated with a lower risk of CHD in women.

Assessing Produce Effect on Nurse’s Health Study (NHS) & Health Professionals Follow-up Study (HPFS)
Another study tried to establish an association of quantity and variety in fruit and vegetable intake in relation to incident CHD in the NHS and HPFS study. An FFQ was sent to participants every 4 years to update information on their diet and also the participant’s intake of fruits and vegetables. Average daily intake of individual fruits and vegetables were summed to compute total fruit and vegetable intake. Potatoes, soy and legumes were not included in the definition of vegetables in the FFQ and variety in fruit and vegetable intake was defined as the total number of unique fruits and vegetables consumed at least once per week.

Participants with a higher quantity-adjusted variety score were less likely to smoke, were more physically active and had higher intake of fruits and vegetables and women with higher variety were likelier to use more multivitamins and aspirins. Higher intake of fruits and vegetables were associated with a lower risk of CHD and higher intake of various subgroups including all fruits, all vegetables, citrus fruits, green leafy vegetables and vitamin C-rich foods were associated with a lower CHD risk. Total fruits and vegetables intake showed that risk of CHD was 18% lower in the third quintile compared to 1st quintile but further intake did not decrease the risk.
All these studies clearly show that the amount of vegetables you consume, the variety of the vegetables and the frequency of consumption definitely impact the risk of CHD. The recommendations include 5 portions of fruits and vegetables every day and most adults don’t meet this requirement. It is necessary that each of us take every step possible to fulfill this requirement and stay in good health.

References
Greater Vegetable Variety & Amount are Associated with Lower Prevalence of Coronary Heart Disease: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-018-0376-4
Fruit & Vegetable Intake And Risk of Coronary Heart Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947047/
Quantity and Variety in Fruit and Vegetable Intake and Risk of Coronary Heart Disease: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3831537/