Looking at the Alkaline Diet

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Guest blog by Vicky Ware

Looking at the Alkaline Diet

Can you change your body’s pH? And would you want to? Vicky Ware finds out.

One of the primary aims of your body is to preserve its internal environment with respect to the external environment – known as maintaining ‘homeostasis’.  For example, when healthy your internal temperature stays the same regardless of the temperature around you. The pH of your blood also has an optimum level, this is around 7.4 [1].

There are areas of the body which have a different pH to allow them to function. For example, the stomach is very acidic at pH 1.35-3.5 which allows it to break down the food you eat [2]. A few cell layers away from the stomach is quite alkaline and this prevents tissue damage from the acid in the stomach [3].

Eating a slightly acidic or alkaline diet is not going to alter the pH of your body drastically, and you wouldn’t want it to. What will happen is the pH of your urine will change as your kidneys get rid of the excess acid or alkaline by-products of the food you eat [4]. Your body is working harder to maintain homeostasis than it would be if your diet had a balanced pH.

Hunter gatherers were eating significantly more alkaline diets than modern humans [5], who eat diets poor in magnesium, potassium and fibre whilst rich in (some types of) saturated fat, simple sugars, sodium and chloride [6]. The result of this may be that we are in a state of mild metabolic acidosis which is not ideal for human health [7]. Eating a diet which includes more alkaline foods could therefore be beneficial to health in a number of ways we’ll explore below.

Alkaline Diet and Bone Health

skeleton

A large reservoir of alkaline in your body is the skeleton, and in particular the calcium found there. A diet rich in acidic foods may result in key minerals being released from the skeleton to allow the blood to maintain its pH balance [8]. It has been estimated that the amount of calcium lost in the urine due to an acidic diet could be around half the skeletal mass of calcium over 20 years [9]. The calcium is eventually excreted in the urine, and its presence there leads to the idea that an acidic diet causes osteoporosis. However, long term studies have shown that levels of calcium in the urine do not relate directly to chances of getting osteoporosis [10;11].

Contrasting this is the finding that dietary bicarbonate (a source of alkaline) seemed to stop bone loss in healthy adults [12]. Usually contrasting results in science mean we’re missing a key point, or that the two things we’re looking at are linked, but do not cause each other.

Vitamin D status could be a contributing factor here. Those with adequate vitamin D are able to absorb calcium from the diet, along with magnesium and phosphate which are also required for bone health [13]. This could mean that those who eat an acidic diet are losing calcium from their skeleton in the urine but are able to absorb enough through their diet to replace it and therefore do not get osteoporosis. Those without enough vitamin D (most of the population in the Northern Hemisphere [14]) are not able to replace the calcium they are losing.

Vitamin D is a fat soluble vitamin. Its uptake requires absorption of fat in the intestine [15]. It might therefore be helping prevent calcium leaching from the bones and aiding uptake of calcium from the diet. It is possible that eating fats that are a source of both alkaline and fat for vitamin D absorption, could help you maintain healthy bones.

An interesting note for athletes is that intake of a large amount of protein (which is acidic) has been shown to decrease bone density if the protein is not consumed with alkaline foods [17]. However, protein is a great source of nutrients and paradoxically is required for bone health. The advice is therefore to increase intake of alkaline foods with protein, not decrease protein intake [18].

Banana Chia Smoothie

Alkaline Diet and Muscle

It has been shown that older men and women who have a diet low in acidic foods have greater lean muscle mass than those who eat less alkaline foods [18]. This could be because the kidneys perform less well as we age [19], resulting in mild metabolic acidosis that leads to muscle loss. An alkaline diet could balance this lack of kidney function out. Acute acidosis caused by exhaustive exercise (the burning feeling you get in your legs) has also been shown to be alleviated by dietary supplementation with sodium bicarbonate, which is alkaline. However this study did not show that this improved exercise performance [20].

skeleton

Another advantage of alkaline foods is an increase in growth hormone. Growth hormone aids muscle growth after exercise, but also decreases risk of cardiovascular disease, improves lean body mass and even helps memory and cognition [21]. Neutralising dietary acid intake by eating alkaline foods was shown to significantly increase growth hormone production in post-menopausal women along with markers of bone building which may lead to reduced osteoporosis [8].

Athletes go to great lengths to increase their growth hormone production, a well known way is through napping as you mainly produce the hormone whilst asleep [22]. Administration of growth hormone is banned for athletes in competition, as it is performance enhancing. Naturally increasing your body’s ability to recover through growth hormone production is allowed however and alkaline foods could be a great way to do this.

Problems with Alkaline Diet

A lot of the commercial alkaline diet advice suggests cutting out foods which are actually a good source of nutrients. As always, it is about getting the balance right and eating a lot of fresh fruit and vegetables and unprocessed foods – you shouldn’t have to eat expensive supplements, just real food. .

Vicky.

Vicky has a degree in Biological Sciences with a focus on biochemistry and immunology and is currently studying for a  MSc in Drug Discovery and Protein Biotechnology.  She is also an endurance athlete.

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  • Great information for those wanting to know more about alkaline foods.

    • Many thanks for your comment. Glad you found this informative.

  • Great information for those wanting to know more about alkaline foods.

    • Many thanks for your comment. Glad you found this informative.