KIDNEYS: If You Are Fond of Your Heart, then Care for Your Kidneys

Cardiovascular disease has been the number one killer in New Zealand and most industrialised nations. What is less known is that kidney problems can be the cause of heart and blood pressure problems – as well as high acidity which impedes sleep, digestion, elimination, joints and bones.

It is the bloodstream’s job to ferry nutrients to fuel-hungry cells throughout the body. This critical goal can only be achieved with the help of the kidneys. These bean shaped organs are about the size of a computer mouse. Each is topped by a cap-like Adrenal gland (for my article see website TIPS page) and lies on either side of the spine, just behind and below the lower rib cage. There must be at least one functioning kidney in order to survive.

The kidneys primary function is to constantly filter blood, receiving about 1 litre per minute. So extensive is their busy network of blood vessels that they can contain almost ¼ of your circulating blood at any one time. This lets you eliminate metabolic end products, especially protein-based ones (measurable in urine samples, which indicate removal rate). These are wastes from your 50 trillion factory-like cells, mixed with water and other substances: the minerals potassium, sodium, calcium, magnesium, phosphorous, and chloride; glucose and many drugs. The kidneys can conserve, eliminate or allow these to be reabsorbed.

The urinary system consists of two kidneys, two ureters (tubes from the kidney to the bladder), a bladder (made up of muscular layers for expansion and contraction) and a urethra (tube from the bladder to the outside of the body). The female urethra is much shorter and opens into a more exposed, easily contaminated area. This explains why women are much more likely to develop urinary tract infections (UTI). Each kidney continuously produces urine which drains along the ureters into the bladder until eliminated via the urethra and its voluntarily controlled sphincter. Normally, urine is sterile and free of bacteria and other infectious organisms. In an emergency it can be used as a drink, or to wash a wound. Almost 200 litres of blood is filtered daily. Most of this is reabsorbed leaving an average of 1.5 litres of urine to eliminate. 96% of urine is water and of the remaining solids half is urea (produced in the liver from protein breakdown); the rest is uric acid, ammonia and other wastes.

Key kidney tasks are to help regulate blood acidity and blood pressure (BP). They can lower acidity and BP by excreting excess sodium. They can raise BP by limiting sodium’s release or by producing an enzyme called renin. The kidneys also secrete hormones which stimulate the production of red blood cells in bone marrow (erythropoietin), and affect bone growth (calcitriol). Calcitriol is the hormone-like form of vitamin D, which oversees Strong Bone (TIPS) building by adjusting levels of calcium and phosphorous. In turn, hormones from the pituitary and adrenals govern the kidneys’ regulatory choices.

Suboptimal function may not reveal symptoms to the untrained observer. Tiredness, or accumulated fluid (note swelling around the eyes), or loss of appetite may be all that is noted. Acute or chronic urinary system disorders however usually have one or more of the following symptoms:

• Fever, fatigue, vomiting, nausea;

• Pain in the side or small of the back;

• Itchy skin (from the accumulation of excess metabolic wastes; or due to poor Liver function-TIPS);

• Swelling (commonly in ankles, feet, hands, upper eyelids and below the eye from accumulated fluid);

• Frequent or urgent need to urinate (more than 8 times daily) or inability to fully eliminate;

• Increased output of urine (due to poor ability to concentrate urine or to high glucose levels);

• Decreased output of urine, hesitating, straining, dribbling or uncontrolled loss of urine;

• Needing to get up in the night to urinate (also common to diabetes, poor heart, liver and prostate function);

• Blood in urine (infection, hemorrhage, cancer); changes in odour or colour (urine should be nearly colourless unless affected by medications, supplements); cloudy and foul smelling indicates infection (such as cystitis); deep yellow and strong smelling indicates dehydration; dark can indicate hepatitis.

Incomplete elimination of urine encourages chronic infections and vice versa. Such infections can travel to kidneys and lead to permanent damage that only dialysis or a transplant can rectify. Diabetes is the most common cause of kidney failure. Next in line is hypertension or high BP which leads to kidney problems, just as kidney problems can lead to high BP. With decreased kidney clearance of uric acid (from protein metabolism) gout can occur. This is a form of arthritis where uric acid crystals accumulate painfully in inflamed joints and extremities such as the big toe.

Uric acid can also aggregate as kidney stones. Although such blockages are 80% likely to be composed of calcium salts (from high excretion rates more than dietary intake). Oxalates are food components that in excess can also bind with and eliminate minerals such as calcium and magnesium (which should instead be stored in bones and muscles like the heart). Oxalates are high in beer, spinach, rhubarb, chocolate, black leaf tea, and peanuts. Sufficient B6 (brewers/savoury yeast, wholegrains, nuts, seeds) helps to offset their stone forming potential.

How To Be Kind To Your Kidneys

• Drink high quality fluids (2 litres daily of purified water, herb tea, broth, up to 1 glass unsweetened juice daily – anti-bacterial cranberry is recommended) to efficiently dilute and remove wastes.

• Minimise diuretics (substances that force out water and minerals): Caffeine-TIPS (coffee, black leaf tea, cocoa–2 x week max; soft drinks, energy drinks), Alcohol-TIPS(1 unit/120 ml wine/1 beer for women or 2 units for men per day max, no more than 2 x week), and highly sweetened drinks (once per week if any). Soft drinks are very high in phosphorous; in excess it promotes excretion of Calcium and Magnesium (TIPS). The liver needs 8 hours to process caffeine so avoid in afternoon if sleep is troubled. If you wake to urinate then avoid diuretics in the afternoon and all drinks for 2 hours before sleep. Poor Sleep (TIPS) taxes adrenals/kidneys, as do multiple Medications (TIPS) especially Pain (TIPS) relievers.

• Replace easily excreted minerals (especially magnesium which is needed for others to enter cell and to increase the solubility of calcium) critical for muscle and nerve function, fluid balance, Brain (TIPS) messages, digestion, bones, joints, stress management and sleep. But don’t over-supplement with any single mineral or others can become imbalanced. Top sources of most minerals: nuts, seeds, seaweed, fish, seafood, stock (made from bones boiled with lemon juice or vinegar to extract their minerals); followed by dried fruit (especially prunes, figs, dates), and lastly leafy greens.

• Eat top soluble fibre sources (psyllium, linseed, prunes, figs, rice bran, oat bran, mango, seaweed – see The Shape Diet for more on how/why/when) which helps keep excreted material soluble rather than stone forming, decreases mineral excretion, and is #1 in regulating blood sugar and insulin levels for weight management and cardiovascular health. Japanese research links 3 tsp rice bran powder daily with a six-fold reduction in stone recurrence. Eat insoluble fibre (wholegrains, vegetables, fruit) for regular, thorough elimination or a full rectum can lead to bladder pressure and urine retention.

• Eat a balance of plant Protein-TIPS (Legumes including soy, grains, nuts, seeds, with a small amount in some vegetables), to animal protein (egg, animal milks, fish, seafood, meat). See The Shape Diet questionnaire to determine which food sources suit your body type best. Excess protein means more work for your kidneys and liver to filter. This produces ammonia and other by-products especially toxic to the brain (often unpleasantly evident on the breath). Excess acidity draws minerals from bone storage as neutralisers (increase alkaline leafy greens, fruit, Chlorofresh drink – health store).

• Minimise processed Sugar (TIPS): the preferred food for infectious bacteria (within minutes it weakens the ability of the immune system’s white blood cells to engulf and destroy invaders). Its high acidity causes a rise in urinary calcium and magnesium excretion; it encourages spiking blood sugar and Inflammation (TIPS). Keep desserts to once per week. Use fresh/dried fruit and spices to sweeten cereal, snacks and baking (RECIPES). Try bars with no added sugar (or even more toxic artificial sweeteners) such as Larabars; or raw chocolate (health stores).

• Maintain a healthy Weight. Being overweight, diabetic, or insulin resistant – common to the thin as well (see my client information sheet: Blood Sugar Regulation) encourages the loss of those key regulating Minerals (TIPS) via excessive insulin release. Regular exercise and improving your muscle to fat ratio is particularly helpful in establishing healthy, insulin sensitive cells instead.

• Keep your kidneys’ mate the cardiovascular system healthy too (see HEALTH STORE for my report: The Heart of the Matter). Conveniently this likewise involves maintaining a healthy weight, insulin sensitivity, regular exercise, good mineral levels, soluble fibre and B vitamins. Also feature vitamin E (nuts, seeds), vitamin C (raw fruit and vegetables, especially kiwifruit and red capsicum), Omega 3 (dark oily fish, whole linseed – see The Shape Diet for my Linseed Cereal recipe), and selenium (brazils, mushrooms, fish).

Maria Middlestead Reg.Clinical Nutritionist, Auckland Call Today!

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