Attenuate Hypertension Risk with Amplified Antioxidant Intake

Antioxidants for Reduced BP: Fresh Food Fetches Benefits than Fortified Supplements

We see almost none without hypertension or sugar once individuals cross their 50s as these chronic diseases are extremely prevalent and common these days even in those in theirs 20, 30s and 40s. Any individual going for a diagnosis or health check up to the doctor is immediately checked for his/her BP levels and also questioned on medical history to gauge whether hypertension was the result of improper lifestyle habits or something beyond that-such as stress or genes. We live in a competitive world that offers us with ample opportunities to learn, enjoy and be happy in life as well as corners us with its overexposure and cut-throat competition that makes individuals treat each other as enemies or competitors rather than as fellow citizens who wish to succeed in life. Such attitudes and challenges increase stress levels which indeed affect blood pressure levels. Hypertension (HTN) is a global health problem existing as the foremost cardiovascular risk factor worldwide contributing to more than 50% of prevalent coronary heart disease and almost 2/3rd of cerebrovascular disease burden. There does exist the fact that hypertension is genetic but our lifestyle methodologies including diet such as too much of sugar and salt or too little of antioxidant vitamins play primary roles in deciding upon hypertension risk.
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Antioxidant-Reactive Oxygen Species-Hypertension
Cardiovascular disease is seen along with enhanced oxidative stress (OS) in the vascular wall, heart, kidney and brain. OS induces inflammation, endothelial dysfunction and increased vascular tone resulting in vascular contractility, structural remodeling and hypertension. The process by which reactive oxygen species (ROS) are conveyed is not entirely clear and also the relationship between hypertension, antioxidants and oxidative stress is quite complex and not fully understood. We have several studies showing that hypertension may develop due to increase in reactive oxygen species and also that antioxidants definitely help in relieving hypertension burden. ROS paves way for vasoconstriction and increased vascular resistance by altering balance in the endothelium between vasoconstrictors such as thromboxane and isoprostanes and vasodilators such as nitric oxide. On the other hand, oxidative stress raises blood pressure by promoting nitric oxide deficiency, augmenting arachidonic acid oxidation and formation of vasoconstrictive prostaglandin. This oxidative stress which creates an imbalance between pro-oxidants and antioxidants thereby resulting in startling changes in the endothelial cells plays a critical role in the development of hypertension.

Antioxidants have become very much popular these days as they seem to fight against free radicals and inhibit oxidation. Free radicals are unstable molecules formed during normal cell metabolism. They build up within cells and affect nearby molecules such as proteins and lipids thereby increasing the risk of diseases. Certain studies show that specific antioxidant vitamins such as vitamins C and E and pro-vitamins such as beta-carotene are majorly involved in preventing diseases but this approach seems ineffective rather harmful as it almost increases rather than decreasing the risk of cancer and cardiovascular events or mortality rates. This paved way for other studies that probed into the antioxidant potential of other food components including vegetables, specifically polyphenols and their impact on hypertension. Such contradictory results led to the assessment of total antioxidant capacity (TAC) of different foods or whole diets rather than analyzing individual dietary antioxidant nutrient intakes. This is made possible by the use of two methods-hydrogen atom transfer (HAT) and single electron transfer (SET). The total radical-trapping ability parameter (TRAP) is a HAT assay for measuring dietary TAC. Having a clear picture of mean daily TAC intake would greatly help us in getting a clearer picture of how dietary modifications can reduce the risk of health conditions such as colorectal cancer, gastric cancer, myocardial infarction, stroke, type 2 diabetes risk and mortality rates. But sadly, we don’t have any studies showing a definite link between dietary TAC and hypertension risk. A French cohort study tried to analyze this relationship by studying 98,995 women aged 40-65 years.

French Cohort Study
The E3N French study mainly wanted to analyze the risk factors of cancer and chronic diseases. Hence, filled questionnaires on lifestyle and disease occurrence were sent by participants every 2-3 years. The response rate for every cycle was almost 83% and the loss in follow-up rate was 3%. The study started in 1990 and in 1993, 74,520 participants responded to a questionnaire that probed into the diet history of the participants. Many women including those consuming high proportions of energy, those suffering from cancer, hypertension or cardiovascular diseases before or during the 1993 questionnaire were excluding thereby leaving the study team with only 40,576 women.

The self-administered diet history two-prat questionnaire contained 208 items. The first part probed into the consumption frequency and portion sizes of 66 food groups and frequency was measures based on 11 different categorizations-never or less than once a month; 1,2 or 3 times a month and 1 to 7 times a week. There was a photo booklet attached to the questionnaire to help in evaluating portion sizes. The second part of the questionnaire helped in segregating the 208 food items or beverages into respectable food groups. For every food item present in the questionnaire an equivalent food item was identified in the TAC database. Four food items (apple, melon, beer and vinegar) had more than 2 values and hence the average of the values was considered. For any food whose match couldn’t be found in the database a similar food that has the same vitamin C and E, polyphenol content and botanical group were measured. TRAP helped to measure the TAC of foods and the database showed that TRAP from coffee represented 75% of overall dietary TRAP, 6% for fruit, 5% for wine, 5% for tea, 4% for vegetables and 3% each for chocolate and other sources. Just because coffee dominated the list, the study team split the model into two: coffee-TRAP and non-coffee TRAP. In the non-coffee TRAP group, the providers were as follows: fruits (22%), wine (20%), tea (18%), vegetables (16%), chocolate (12%) and other sources (12%). Participants were questioned on their daily intake of different nutrients and energy intake was calculated accordingly. Physical activity performed in terms of walking, cycling, swimming and performing light or vigorous household chores were noted down in the questionnaire. Metabolic equivalents (MET) per week were noted down by multiplying yearly average METs for every item based on values from the Compendium of Physical Activities by the reported activity duration. Height, weight and BMI measurements were calculated and energy intake and total antioxidant capacity was estimated from the dietary questionnaire.

Results
After following up for almost 13 years and 4,93,895 person-years results showed that:

1. There were 9350 cases of hypertension reported (18.9 cases per 1000 person-years) the average age was around 51.6±6.2 years and the mean TAC was 20.3±14.1 mmol/day. It was 5.2±1.7 mmol/day in the first quintile and 42.1±12.7 mmol/day in the fifth quintile.
2. TAC intake was inversely associated with hypertension. Non-coffee TAC was linked with a reduced risk of hypertension from the second quintile but with respect to coffee TAC an inverse association was seen only in the fifth quintile.
3. Dietary TAC from wine, fruits and vegetables and other sources were inversely associated with risk of hypertension while TAC from coffee, tea and chocolate were not
   
   

The study clearly proved that high antioxidant capacity was associated with a reduced risk of incident hypertension specifically when the antioxidant source was something other than coffee.

We do have other studies showing that increased intake of fruits and vegetables can reduce blood pressure in hypertensive and normotensive patients. In a study where the diet of hypertensive participants increased vegetable and fruits intake for the 6-month study period results showed a blood antioxidant capacity and decrease in systolic and diastolic blood pressure. But we do have studies showing that antioxidant supplements have no effect in improving hypertension levels. One study carried on for 5 years showed that blood pressure levels did not improve even after the participants were treated with a mix of vitamin C, vitamin E and beta-carotene versus placebo. Consuming fresh fruits and vegetables is an excellent way to improve antioxidant capacity. Choosing supplements prove to be ineffective.

References
High Dietary Total Antioxidant Capacity is Associated with a Reduced Risk of Hypertension in French Women: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-019-0456-0
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Antioxidant Supplementation in Hypertension: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4206049/