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Managing blood pressure – not just about sodium

Posted by The Healthy Eating Hub

Blood pressure measures the force exerted by our blood against the walls of our blood vessels. Hypertension is the medical name for high blood pressure.

When a person has hypertension, their blood is applying too much force against the walls of their blood vessels, which causes the blood flow to become turbulent. Imagine a garden hose – if we block the end of the hose and increase the speed of the water, the pressure increases and the hose may become damaged. The same principle is true for our blood vessels.

It is well known that unmanaged hypertension can lead to cardiovascular diseases, such as a heart attack or stroke. Turbulent blood flow weakens blood vessels and increases the risk of clot formation in the arteries.

One in five

New Zealand adults has high blood pressure1

Is it all about sodium?

Most of us have heard the word ‘sodium’ and its connection to high blood pressure. This is true. Sodium (found in salt and other food sources) is an essential electrolyte that our body needs for day-to-day functioning, however eating too much has long been identified with increased risk of high blood pressure. The result of consuming a diet high in sodium is water retention. Retaining excess water negatively influences our normal water balance in and out of the cells, causing blood pressure to rise. Salt reduction in the food supply is the most common effort to reduce blood pressure population-wide.2

What many people may not know about is the other nutrient interactions that affect blood pressure. In addition to putting down the salt shaker, there are other important nutritional factors to consider when trying to reduce blood pressure through dietary changes.

Key nutrient interactions that affect blood pressure

We do not consume nutrients individually; rather, we consume food as part of a whole diet whereby nutrients interact with one another.2 The sodium-potassium and sodium-calcium nutrient interplays are understood to lower blood pressure due to the ability of these nutrients to increase the excretion and eliminate of sodium through the urine.2,3 Research has suggested that consuming foods rich in naturally occurring potassium and calcium can help to lower blood pressure risk.2,3

This understanding highlights the importance of considering the diet as a whole (combined nutrients) and its effect on blood pressure.

Potassium

Research has shown that intake of potassium through dietary sources contributes to lowering blood pressure in individuals with and without hypertension.4 Potassium is important for muscle function and helps the walls of our blood vessels to relax. This is a key reason potassium helps to lower blood pressure.

Increasing our overall intake of potassium (while simultaneously reducing our sodium intake) has been shown to drastically reduce the incidences of conditions associated with cardiovascular disease.5

Natural sources of potassium include:

  • kale
  • spinach
  • arugula (rocket)
  • bananas
  • nuts and seeds
  • apricots
  • avocados
  • potatoes
  • mushrooms.

There are many practical ways to include potassium in your everyday diet.

  • Add kale to your stir fries.
  • Enjoy baby spinach in your omelette.
  • Add a banana to your smoothie.
  • Toss fresh or dried apricots into your natural yogurt.
  • Spread ¼ avocado on your multigrain toast.

Calcium

Most of us have heard that calcium is an important nutrient crucial for healthy bones. While this is true, calcium also plays an important role in achieving a healthy blood pressure because it helps blood vessels constrict and relax when they need to. Similar to potassium, current research has shown that increasing calcium intake lowers blood pressure in individuals with and without hypertension.6 This is especially important for children and young adults as blood pressure in childhood can be associated with blood pressure in later life.

Natural sources of calcium include:

  • milk and milk products
  • leafy green vegetables, eg, broccoli, cabbage, spinach
  • soy and tofu
  • fish (sardines and salmon with bones)
  • nuts and seeds, eg, brazil nuts, almonds and sesame seed paste (tahini).

Calcium can easily be included in your everyday diet.

  • Add leafy greens (frozen and thawed, or fresh) to a frittata.
  • Try some tofu in your stir fries.
  • Add yoghurt – incorporate into your soup, have as a salad dressing or use in a dip, eg, tzatziki.
  • Take a handful of nuts to work as a quick snack.
  • Toss tinned salmon through a salad.

Variety is key

Good health has long been associated with a varied diet that’s rich in minimally processed or whole foods. Research suggests that dietary patterns following a higher consumption of fruit, vegetables, whole grains, legumes, seeds, nuts, fish and dairy, and a lower consumption of fatty meat, confectionery items and alcohol significantly lower blood pressure.2

Best combination for success

Adopting an overall healthy diet that is diverse in whole foods in combination with regular physical activity is the best long-term strategy to combat high blood pressure. This will simultaneously reduce our sodium intake and increase our consumption of natural sources of potassium and calcium.

Practical tips to add flavour to your foods

Flavour doesn’t have to be sacrificed when we put the salt shaker away and start incorporating a wide range of whole foods. We can reduce salt intake with some clever kitchen creativity.7

Try out these flavour combinations:

  • Pork: garlic, lemon rind, coriander, apple sauce, ginger, mustard
  • Beef: bay leaf, thyme, sage
  • Lamb: mint, ginger, currant jelly, paprika, oregano, rosemary, garlic
  • Chicken: sage, tarragon, garlic, chilli
  • Fish: lemon juice, pepper, lime juice, chives, parsley, vinegar
  • Tomato: basil, garlic, black pepper, parsley, oregano
  • Potato: chives, paprika, mint, parsley, black pepper
  • Carrots: ginger, cinnamon, honey, parsley.

References

  1. Ministry of Health. 2016. Annual Update of Key Results 2015/16: New Zealand Health Survey. Wellington: Ministry of Health.

  2. Ndanukd RN et al. Dietary Patterns and Blood Pressure in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials, Adv Nutr. 2016;7(1):76-89.
  3. Whelton PK et al. Effects of Oral Potassium on Blood Pressure: Meta-analysis of Randomized Controlled Clinical Trials, JAMA. 1997;277(20):1624-1632.
  4. Curr MC. The Importance of Potassium in Managing Hypertension, Hypertens Rep. 2011;13(4):309-317.
  5. Margerison C et al. Dietary sources and meal distribution of sodium and potassium in a sample of Australian adults, Nutr Diet. 2013; 70: 294-299.
  6. Cormick G et al. Calcium supplementation for prevention of primary hypertension (review), Cochrane Database of Systematic Reviews. 2015;(5):1-98.
  7. Queensland Health, Nutrition Education Materials Online. 2017, accessed 6 June 2019 www.health.qld.gov.au/__data/assets/pdf_file/0034/147877/cardiac_salt.pdf

About the author

The Healthy Eating Hub

The Healthy Eating Hub is a team of university qualified nutritionists and dietitians who are passionate about helping people develop long term healthy eating habits through offering evidenced-based and practical nutrition advice that people can put into practice straight away.

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