Introduction
Hypertension, also known as high blood pressure, is a phenomenon that occurs when the pressure in our blood vessels is 140/90 mmHg or higher. It is a common occurrence but can lead to serious impacts if left untreated. The WHO states that about 46% of adults with high blood pressure are unaware that they have it.
Some of the best fruits that help lower blood pressure are berries. Blueberries are a good example here. But, did you know that pineapples are also berries? They are a group of merged berries, making them a multiple fruit. In this article, we shall go ahead and review what makes pineapples good for hypertension.
Nutritional composition of pineapple
To understand how pineapple helps to reduce hypertension we have to learn about its constituents.
The nutritional content of 148g of pineapple is described in the table below:
Type | Name | Amount |
Vitamins | Vitamin A Vitamin B-6 Vitamin C Vitamin E (alpha-tocopherol) | 4.95 µg 0.185 mg 78.9 mg 0.033 mg |
Minerals | Calcium Copper Iron Sodium Magnesium Manganese Phosphorus Potassium Selenium Zinc | 21.4 mg 0.181 mg 0.478 mg 1.65 mg 19.8 g 1.53 mg 13.2 mg 180 mg 0.165 µg 0.198 mg |
Although all the vitamins and minerals composing pineapple are beneficial, however, certain components because of their higher concentration produce a slightly greater effect than others, since we are discussing hypertension, we will highlight:
- Potassium
- Vitamin C
- Bromalin
These components produce the desired effect for reducing blood pressure.
The role of potassium in blood pressure regulation
Pineapples are a great source of potassium which plays a beneficial role in reducing blood pressure by counteracting the impact of sodium in our bodies. Excessive sodium intake can elevate blood pressure, but by increasing potassium consumption, we can mitigate these effects.1
Potassium promotes the elimination of excess sodium through urine, leading to a decrease in blood volume and ultimately lowering blood pressure. Moreover, potassium has the added benefit of relaxing blood vessel walls, further contributing to the reduction of blood pressure.1
The recommended daily amount of potassium by the World Health Organisation (WHO) is at least 90 mmol/day for adults, and for children depending on their energy requirements, it is lower. Besides blueberries, other foods rich in potassium are unrefined foods like beans, peas, nuts, spinach, dates, and papayas.
Vitamin C and its benefits
Research has emphasised the crucial role of the inner lining of blood vessels, the endothelium, in vascular health and its connection to vitamin C's impact on blood pressure.2 In people with high blood pressure, the ability of blood vessels to widen (called endothelial vasodilation) does not work well. The antioxidant properties of vitamin C seem to help improve this widening of blood vessels.3
Vitamin C, or ascorbic acid, found in abundance in pineapples, is a vitamin that is soluble in water, which means that it can easily be transported to body tissues by being dissolved in water.
Moreover, clinical studies, such as those conducted on large cohorts like the Nurses Health Study and the Health Professionals Follow-up Study, have indicated a promising association between vitamin C intake, circulating levels of vitamin C in the blood, and a lower risk of hypertension.2
Some studies have also suggested that the effects of vitamin C supplementation on blood pressure might vary with age and gender. For instance, reductions in diastolic blood pressure were observed in the subgroup of hypertensive patients aged 60 years and older.2
However, Vitamin C cannot be stored well by the body, therefore, it needs to be consumed daily through foods like citrus fruits, or supplements.
The recommended daily amount of Vitamin C lies between 85mg and 90mg for adults and Pineapples have about a third of this recommended amount.
Bromelain and blood pressure
Bromelain is a group of enzymes that break down proteins, and it's mostly found in various parts of the pineapple plant, like the peels, leaves, stems, and fruit, but higher concentrations are found in the stem and fruit.4 It possesses fibrinolytic properties.4 This means that it can dissolve fibrin, a protein involved in the formation of blood clots (thrombus).
PAI-1, or plasminogen activator inhibitor-1, is a protein that essentially acts as a traffic controller for breaking down blood clots. It inhibits enzymes like tissue plasminogen activator (tPA) and urokinase (uPA), which are responsible for dissolving these clots through the process of fibrinolysis.5
Plasminogen, the inactive form of plasmin, is converted to plasmin by tPA and uPA. Plasmin then activates tPA and uPA, which creates a positive feedback loop that initiates a self-reinforcing cycle, promoting further activation of plasminogen.
This feedback loop holds significant importance in efficiently clearing blood clots that have fulfilled their purpose. Bromelain proves to be an effective fibrinolytic agent by stimulating the conversion of plasminogen into plasmin, further increasing the process of fibrinolysis.6
But how can lower clearing of blood clots lead to higher blood pressure? If a blood clot moves to the kidneys, it can raise blood pressure and possibly damage or make the kidneys fail. Blood clots can also cause high blood pressure by causing a pulmonary embolism, a condition where blood clots are present in the lung arteries.
Potential limitations and considerations
There are various ways people can react to pineapples:
- Mucosal Irritation: Bromelain in pineapples can cause burning and soreness in the mouth due to its acidic nature. Heating pineapple denatures bromelain, so symptoms are more likely with fresh pineapple. Pairing it with dairy or salt can help alleviate symptoms.
- Oral Allergy Syndrome: Symptoms include itching and swelling of the lips and tongue. Due to cross-reactivity, people allergic to birch tree pollen may experience similar symptoms with pineapples. Heating the fruit or avoiding it is the recommended treatment.
- Anaphylaxis: This severe reaction involves hives, swelling, wheezing, coughing, vomiting, diarrhoea, and low blood pressure. Various tests, including allergy skin and specific IgE lab testing, can help diagnose pineapple allergies.
Different individuals may experience pineapple reactions differently, and consulting an allergist for appropriate testing is crucial to establish or rule out a clinical allergy diagnosis.
Besides allergies to pineapples, bromelain consumption in the following cases is also not recommended:
- Breastfeeding or pregnant
- While taking blood thinners like Jantoven (warfarin), Lovenox (heparin), or even aspirin
- When undertaking surgery
- Having received a diagnosis of liver or kidney disorders
- When suffering from peptic ulcers or other digestive issues
Incorporating pineapple into a heart-healthy diet
There are several ways pineapple can be incorporated into our diet:
- Eating freshly cut pineapple chunks alone or with other fruits like blueberries and raspberries in a fruit salad
- Consuming frozen or canned pineapples, though if canned, it’s recommended to have them if they are packed in their juice and not syrup due to how sweet pineapples already are on their own
- Grilled pineapples topped with lime and mint chutney
- As the controversial pizza topping
- Having it with yoghurt
- Making pineapple raspberry popsicles
While pineapples promise potential blood pressure regulation, they alone may not suffice. A holistic approach to cardiovascular health, including regular fitness and broader dietary considerations, is essential.
Pineapples can be part of a balanced diet, but consulting a medical professional is crucial for personalised advice, especially for individuals with existing health conditions or on specific medications.
Summary
The diverse nutritional composition of pineapples, encompassing key elements such as potassium, vitamin C, and bromelain, suggests their potential as a beneficial addition to a heart-healthy diet for individuals concerned about blood pressure regulation.
The potassium content counteracts the hypertensive effects of sodium, vitamin C's antioxidant properties support endothelial health, and bromelain exhibits fibrinolytic abilities, aiding in blood clot dissolution.
However, it is crucial for individuals to be aware of potential allergic reactions and contraindications, as highlighted in the article, and to consult with healthcare professionals when incorporating pineapples into their diet, especially in specific medical conditions or while taking certain medications.
By understanding the potential benefits and limitations, individuals can make informed choices to promote cardiovascular health while enjoying the versatile and delicious inclusion of pineapples in their meals.
References:
- Burnier M. Should we eat more potassium to better control blood pressure in hypertension? Nephrology Dialysis Transplantation [Internet]. 2019 Feb 1 [cited 2023 Nov 24];34(2):184–93. Available from: https://academic.oup.com/ndt/article/34/2/184/4782766
- Morelli MB, Gambardella J, Castellanos V, Trimarco V, Santulli G. Vitamin C and cardiovascular disease: an update. Antioxidants (Basel) [Internet]. 2020 Dec 3 [cited 2023 Nov 24];9(12):1227. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7761826/
- Taddei S, Virdis A, Ghiadoni L, Magagna A, Salvetti A. Vitamin C improves endothelium-dependent vasodilation by restoring nitric oxide activity in essential hypertension. Circulation [Internet]. 1998 Jun 9 [cited 2023 Nov 24];97(22):2222–9. Available from: https://www.ahajournals.org/doi/10.1161/01.CIR.97.22.2222
- Colletti A, Li S, Marengo M, Adinolfi S, Cravotto G. Recent advances and insights into bromelain processing, pharmacokinetics and therapeutic uses. Applied Sciences [Internet]. 2021 Jan [cited 2023 Nov 24];11(18):8428. Available from: https://www.mdpi.com/2076-3417/11/18/8428
- Lin H, Xu L, Yu S, Hong W, Huang M, Xu P. Therapeutics targeting the fibrinolytic system. Exp Mol Med [Internet]. 2020 Mar [cited 2023 Nov 24];52(3):367–79. Available from: https://www.nature.com/articles/s12276-020-0397-x
- Pavan R, Jain S, Shraddha, Kumar A. Properties and therapeutic application of bromelain: a review. Biotechnol Res Int [Internet]. 2012 [cited 2023 Nov 24];2012:976203. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529416/