A frank beta carotene deficiency although rare leads ultimately to death; however a moderate shortage is very common, affecting many tissues of the body because of the dearth of fresh yellow and orange foods in the Western diet.
A deficiency of this phytochemical causes a pimply skin, poor vision, weak bones, poor resistance to infections and a host of serious metastatic diseases; that is not small beer.
In any case, vegetables like butternut are among my favourites, if you know how to prepare them; often a herb or spice brings out the flavour.
This page was last updated by Dr Bernard Preston on 27th May, 2020.
It comes increasingly in a world that has been hoodwinked into believing that well-being comes in capsules rather from your food. If I do not get enough vitamin E, or beta carotene, then I can just take a pill. Is that not right? No, it is not. Increasingly researchers are saying that the particular substance is less well absorbed, deposited in the wrong places and has other side-effects.
Lack of attention to vitality is additive. For example, if you have a marginal deficiency, and you are stuck all day in front of a computer or, heaven forbid, the television then women in particular are almost certain to suffer from disabling fractures of their bones when they get older.
In fact hip fractures are now beginning to happen before fifty years of age because of our poor diet and sedentary existence; this does not just happen to other people. Soured milk as in kefir incidentally is one of the best sources of calcium.
Cooking some vegetables like carrots actually increases the bioavailability of beta-carotene.
A full blown beta carotene deficiency is rare as this important precursor to vitamin A is found in many vegetables and fruits. Nevertheless many have a moderate, yet serious shortage from their diets; taking it in pill form is unnecessary and potentially dangerous.
You have to be a real meat and potatoes man to become frankly inadequate and actually die from an insufficiency.
Let us talk first just for a moment about colour. An object would appear white because it absorbes none of the spectrum, but it would look orange or yellow if the greens and blues are taken up by the pigments in the material.
Beta-carotene has a structure with alternating double bonds, if you want to know about the chemistry, that absorbe those other colours but not the yellow which is then reflected to our eyes, so we perceive it as having an orangey appearance.
So a beta carotene deficiency means you would not perceive colours well either.
Beta-carotene is the molecule found in foods such as butternut, pumpkins, carrots, sweetcorn and the yolk of an egg that gives them their orange colour. It's an extremely important phytochemical without which we cannot be healthy. The RDA is around 10,000 units per day.
Probably its most important function - but let us not underestimate its anti-oxidant properties that mop up free radicals preventing cancer - is by splitting in two in the liver it is changed into a compound called retinol, which is vitamin A.
Insufficient beta-carotene rich foods in the diet means you will be deficient in vitamin A; now it becomes serious.
The eye is a most wonderful organ, and highly complex; vitamin A, as we've said retinol, is changed to another form called retinal (the aldehyde for the chemistry bofs) which then combines with a group of proteins in the retina called opsins; when light strikes them, like a photovoltaic panel, they turn the energy into an electrical impulse.
That passes down the optic nerve and ultimately we can see an object when it reaches the visual cortex. We are fearfully and wonderfully made, but a beta-carotene deficiency will ruin it all. However, it is not as simple as it would seem.
"Beta-carotene supplementation has been found to be associated with increased risk of tumours in smokers. And studies have found a small but significant increase in all-cause mortality in those taking high doses of vitamin E supplements."
- Dr Alice H. Lichtrenstein, DSc.
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So, vitamin A, alongside lutein and zeaxanthin are vitally important phytochemicals that enable us to see properly and not go prematurely blind; a deficiency is the cause of age-related macular degeneration and cataracts.
One cannot go all day worrying about whether we have eaten enough of this and that phytochemical; there are thousands and keeping track would be impossible and drive us crazy. There is a simple solution; enjoy at least seven to ten coloured foods every day; then you can be sure you'll be getting enough of most or all of them.
You cannot easily overdose with beta-carotene from your food, but you certainly can if you are taking supplements of beta-carotene or vitamin A; let your food be your medicine.
The exception is large amounts of liver, particularly from animals that eat a lot of fish. From plant sources it is not as well absorbed, and overdosing is impossible; more likely a beta carotene deficiency. Enjoying it with a little fat improves the absorption so we have plenty of butter with our vegetables or avocado and olive oil with salads; the fat also lowers the glycemic index, not unimportant in those who are prediabetic.
From our food, there is a decreased risk of lung cancer, but numerous studies have shown that high doses of supplements, particularly in smokers, actually increases the possibility of malignant tumours.(1)
A beta-carotene deficiency has a profound effect on bone strength; the phytochemical stimulates the osteoblasts, the cells that lay down new tissue.
However, an overdose also stimulates the osteoclasts that break down bone; this can never happen from plants sources of the vitamin but can from supplements and large amounts of liver in the diet.
Adequate potassium from our food is vital too, and with less than two percent of Americans enjoying the required 4,000 mg per day, is it any wonder that diseases related to blood pressure, and osteoporosis are so prevalent?
One average avocado provides nearly 1,000 grams of potassium.
This roasted butternut squash recipe is definitely my favourite source of beta-carotene. One cup will provide you with sufficient for all your needs each day. Growing butternut squash is an easy vegetable to plant, but you do need a large garden; it's also one of those gourds that keep for long periods of time, so by all means get it from the greengrocer.
Its favourite spot is in the compost heap; then you can be sure the nutrients will be far superior to anything from a commercial farmer, but one can't grow everything. These organic butternut are a wonder; unlike giant pumpkins it is so sweet.
What's the difference between our easy butternut squash soup recipe and a supermarket butternut squash soup recipe? Chalk and cheese. I make no apology for the time spent in preparing food from scratch; it tastes and is far superior, preventing a awful lot more than just a beta-carotene deficiency.
Either you spend a few extra minutes on healthy choice foods, superior in taste in every way, or you'll spend a lot more time consulting doctors about your cataracts, high blood pressure, diabetes and many other even more serious diseases.
Our favourite way of preparing most foods that would prevent a beta carotene deficiency is by solar pressure cooking; roasting is great too but has a higher glycemic index.
Making a perfect butternut smoothie for breakfast takes only a few minutes if you have some of the soup on hand.
Growing zucchini is another of our favourites, particularly because they are also one of the few sources of two other very important phytochemicals for the eyes, lutein and zeaxanthin.
These are the plants from our garden that are what we call phytochemical foods; they supply the vast range of needed substances that you simply cannot measure; there are over 600 carotenes alone for example. Trying to keep a measure of them all will simply lead to what I call a health nut neurosis; and to be honest, it is a serious psychological condition that I myself have had to face; do not go totally overboard.
Just get your face, hands and feet thoroughly underwater, only not your brain! These buttered gem squash are another favourite; notice the breadth of food that we are advocating, all unrefined and rich in colour.
Your citrus fruit list is another excellent source of vitamins and phytochemicals that will prevent any suggestion of a beta-carotene deficiency. Whether it's lime marmalade or a mandarin orange tree, they all contribute.
Planting sweet potatoes is definitely only for the larger garden, but they actually top the list in the prevention of beta-carotene deficiency stakes. They don't keep as well as butternut and should be kept in the refrigerator and eaten fairly quickly.
Grilled mealies are another great way to get plenty of beta-carotene, and zeaxanthin which is so important in the prevention of macular degeneration.
Carrots of course are another excellent way to prevent a beta carotene deficiency; but raw or cooked?
Livny et al researched the question, comparing the bioavailability of beta-carotene from cooked and pureed vs raw and chopped carrots. Both in fact were a good source, but 50% more was absorbed from the cooked version of carrots.(2)
The pepper family, especially those sweet red paprikas, are the richest source of beta-carotene. They are very easy to grow in a mild climate though staking them can be a challenge; when in fruit, the branches are very heavy.
We just love the sweet 'punt paprika' that we got from Holland, and peppadews for a little spice. Both are so easy to grow in your own garden. Make sure your family doesn't suffer from a beta carotene deficiency.
Growing peppadews is a breeze. They are my favourite from the chili family; oodles of flavour and not too hot. The easiest way to preserve them for the rest of the year is to freeze them, but we also pickle and dry them and turn them into a peppery powder. Adds a little spice to any egg recipe.
Supplements with the exception of folate generally showed no benefit for CV outcomes or death from any cause.
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