Be Careful Juicing....

[Victor]

I happen to love juicing but there is such a thing as too much of a
good thing. I've been juicing kale/spinach/carrots/beets and ginger/
apple J for to taste a couple of times a week. Recently my vision
went blurry for no good reason. Google search turned up blurry vision
as first sign of Vitamin A overdose! Kale, Spinach, Carrots and beets
all have massive amounts of Vitamin A. Now I'm just waiting on my
vision to return as I take a hiatus from the veg juices....

Moral of the story: Overdoing it with vitamins is just as bad as
underdoing it. Though, I prefer to err on the side of too much than
too little.

Vic

[Jerry]

Carrots and leafy plants contain carotenes such as alpha carotene,
beta carotene, gamma carotene. These are converted to vitamin A as
needed. When the body has enough vitamin A, it's supposed to stop
converting carotenes to vitamin A. Therefore excess vitamin A from
plant sources is supposed to be impossible. Or am I misunderstanding
something?

(BTW, one difference between humans and carnivorous animals is we
cannot handle very large quantities of vitamin A (not to be confused
with carotene) and they can.)

There is such a thing as more carotene than the body can use or
store. The extra carotene comes out thru the skin and makes it a nice
orange. Carotenosis. Sounds like a scary disease, but seems to be
harmless. Interesting color of skin.

I doubt your blurry vision was caused by veggy juice. Blurry vision
has a bunch of possible causes. Excess vitamin A has a bunch of
symptoms.

Pesticides in veggy juice might do it. Blurry vision is one possible
symptom of pesticides.

[Victor]

Hmm. Pesticides = doubtful, since I get my juices made at an all
organic store's juice bar. Could be school starting back up and the
accompanying lack of sleep / unrelenting focusing.

According to http://ods.od.nih.gov/factsheets/vitamina.asp :

"Hypervitaminosis A refers to high storage levels of vitamin A in the
body that can lead to toxic symptoms. There are four major adverse
effects of hypervitaminosis A: birth defects, liver abnormalities,
reduced bone mineral density that may result in osteoporosis (see the
previous section), and central nervous system disorders [1,48-49].

Toxic symptoms can also arise after consuming very large amounts of
preformed vitamin A over a short period of time. Signs of acute
toxicity include nausea and vomiting, headache, dizziness, blurred
vision, and muscular uncoordination [1,48-49]. Although
hypervitaminosis A can occur when large amounts of liver [kale/carrot/
spinach juice trump liver in Vitamin A content - my note] are
regularly consumed, most cases result from taking excess amounts of
the nutrient in supplements.

The IOM has established Tolerable Upper Intake Levels (ULs) for
vitamin A that apply to healthy populations [1]. The UL was
established to help prevent the risk of vitamin A toxicity. The risk
of adverse health effects increases at intakes greater than the UL.
The UL does not apply to malnourished individuals receiving vitamin A
either periodically or through fortification programs as a means of
preventing vitamin A deficiency. It also does not apply to individuals
being treated with vitamin A by medical doctors for diseases such as
retinitis pigmentosa."

So according to this source, one CAN consume too many carotenoids and
since my Vit A intake exceeded that of a regular liver consumers' over
the course of about a month or so, it may well be possible that I was
overdoing it.

Vic

[rdp...@gmail.com]

Hi ..... These juice have nitric oxides aswell which dilates the vessels in eye and brain and at times can cause headaches and blurred vision . Do not drink so much .... Everything in life in moderation

[deem...@gmail.com]

Can You Overdose On Vitamins (A & K) With Green Smoothies?
"I love the idea of getting all the vitamins and nutrients via greens but as I run the numbers on how much of each vitamin that is contained in the amount of greens in a typical recipe (i.e. one bunch of spinach), it makes me wonder if you can overdose on the fat soluble vitamins like A and K. I know with supplements in the past you had to be mindful but does your body handle vitamins derived from food sources differently?" -- Andrew

This is an excellent question. I can see how it might be alarming to see vitamin levels that are extremely high in some green smoothie recipes.

For example, a simple green smoothie with one medium banana, one cup strawberries and two cups of fresh baby spinach contains 191% RDA of vitamin A (as beta-carotene) and 245% RDA of vitamin K. That sounds like a lot, but it's nothing compared to the amounts you'd get if you used two cups of kale - 690% RDA vitamin A and 915% RDA vitamin K!

Is It Possible To Overdose On Vitamin A From Green Smoothies?
It is not possible to overdose on vitamin A (retinol) from consumption of "vitamin A-rich" plant foods. Pre-formed vitamin A, also known as retinol, is only found in animal-sourced foods (meat, eggs, dairy). Plants contain beta-carotene, which your body selectively converts to vitamin A (retinol) based on your body's vitamin A status.

If your body requires vitamin A, it will convert beta-carotene. Otherwise, it will store beta-carotene in the liver and body fat without converting it to vitamin A.

It is possible to "overdose" on beta-carotene, however. Carotenosis is a harmless condition where your body stores excess beta-carotene in the fat cells in your skin, giving it a yellow or orange hue. Those with fair complexions are most susceptible to carotenosis than those with darker complexions. There are no other known health effects with carotenosis and the condition reverses itself when beta-carotene is consumed in smaller amounts.

It takes a LOT of beta-carotene to develop carotenosis, however. You're not likely to get it from drinking a green smoothie or two every day. You almost have to get extreme with your overall diet and go out of your way to consume excessive amounts of foods rich in beta-carotene to turn your skin yellow.

Beta-Carotene, Vitamin A and Retinol Activity Equivalents (RAE)

And another thing is that nutrition labels can be misleading about the amount of vitamin A contained in plant foods. Food nutrition labels typically measure beta-carotene in International Units (IUs), but because beta-carotene isn't the same thing as retinol vitamin A, IUs are not the most accurate indication of how much vitamin A activity you are getting from consuming beta carotene.

Retinol equivalent (RE) and retinol activity equivalent (RAE) units have been devised to provide a better interpretation of how much actual vitamin A can be obtained from various foods, including those that contain retinol (meat, eggs, dairy) and those that contains carotenoids like beta-carotene (fruits, vegetables).

According to research published by the US Institute of Health in 2001, 1 RAE is equal to 1 microgram (mcg) of retinol (pre-formed vitamin A) or 12 micrograms of beta-carotene.

So the take home here is that nutrition labels for vitamin A, at least in regards to beta-carotene, aren't exactly the most accurate indication of exactly how much vitamin A you are getting. Your nutrient-tracking software might indicate that a medium carrot contains 340% RDA of vitamin A, but you are not actually consuming more than three times your recommended daily allowance of vitamin A.

Also, your body does not convert excess beta-carotene into excess vitamin A, so there is no risk of overdosing on vitamin A from foods rich in beta-carotene.

What about Vitamin K?
There are two natural forms of vitamin K - K1 and K2. Vitamin K1 (phylloquinone) is found in plants, particularly leafy greens. There are no known toxicity risk with consuming large amounts of vitamin K1 and no "tolerable upper limit" has been set for either vitamin K1 or vitamin K2 (menaquinone).

Basically, a green smoothie that contains almost 1000% RDA for vitamin K presents no toxicity risk in healthy people. However, there are toxicity risks with supplemental and synthetic forms of vitamin K.

I hope this clears up your concern about getting "excess vitamins" from green smoothies, as well as from fruits and vegetables. My health mantra is always "whole foods are best", and when it comes to getting the right amount of nutrients without overdoing it, fresh fruits, vegetables and green smoothies are the safest way to do it.

[Aarchaea.scfs]

> I happen to love juicing but there is such a thing as too much of a
> good thing. I've been juicing kale/spinach/carrots/beets and ginger/
> apple J for to taste a couple of times a week. Recently my vision
> went blurry for no good reason. Google search turned up blurry vision
> as first sign of Vitamin A overdose!

It can also be a symptom of diabetes. Best to get it tested.

Juicing only concentrates the sucrose/fructose in veggies and removes the
greatly beneficial fiber and other elements of the whole plant. You might
as well drink a soda instead in that regard.

[shar...@alaska.edu]

While I agree that moderation and variety is key, I'm kind of hesitant to think that it was the juicing that caused the blurred vision. I agree that over doing juicing can be not such a good thing but drinking a veg drink once or twice a day shouldn't be causing that. You mention you only do it a couple times a week so that makes me think that it isn't juicing that's the cause. Blurred vision is something that should definitely be cause for concern though and probably be checked out by a professional.

[rachel...@gmail.com]

I know "every body is different" but I've been looking for a basic common sense number. I work at a market farm and today brought home about 18lbs of ugly carrots and 8 HUGE red peppers and set about juicing them - so now I've got a few quarts of pure, root vegetable-tasting, local organic carrot & pepper juice.

I got so excited to use it in some recipes and to drink it straight (I love carrot apple juice) but then used a juicing calculator to check up on nutrition. I'm currently, after having one hefty glass, at 22659% of my daily vitamin A.

HOLY COW.

Now, is this something I have to be really careful about? I WebMD'd vitamin A overdose and it listed basically EVERYTHING TERRIBLE THAT CAN HAPPEN TO PEOPLE INCLUDING DEATH as a side effect. Or is it more like, don't do it every day?

Is there a general rule? A magic number that's a good guideline?

Thanks everybody,
Rachel

[crisology]

On Thursday, October 1, 2015 at 6:19:55 PM UTC-4, rachel...@gmail.com wrote:
> after having one hefty glass, at 22659% of my daily vitamin A.

"... diets with high levels of carotenoid-rich food for long periods are not associated with toxicity. The most significant effect of long-term, excess beta-carotene is carotenodermia, a harmless condition in which the skin becomes yellow-orange. This condition can be reversed by discontinuing beta-carotene ingestion" (NIH, 2013).

> Now, is this something I have to be really careful about? I WebMD'd vitamin A overdose and it listed basically EVERYTHING TERRIBLE THAT CAN HAPPEN TO PEOPLE INCLUDING DEATH as a side effect. Or is it more like, don't do it every day?
>
> Is there a general rule? A magic number that's a good guideline?

Beta-carotene from plants is converted to Vitamin A in a regulated ('inefficient') manner, which protects against Vitamin A toxicity (Linus Pauling Institute, 2015) as opposed to preformed Vitamin A in animal products. Unlike preformed vitamin A, beta-carotene is not known to be teratogenic or lead to reproductive toxicity (NIH, 2013). However, consuming one serving of polar bear liver will kill a human due to high Vitamin A content. Pregnant women are generally advised not to consume liver (Dolk, Nau, Hummler & Barlow, 1999). A single serving of beef liver exceeds the known threshold for human Vitamin A Tolerable Upper Intake Levels by a factor of 2.421 (Linus Pauling Institute, 2015), without considering any additional source of preformed vitamin A absorbed in the diet throughout the day. Liver contains excess Vitamin A (among other components) and it is for this reason that liver is often used in Vitamin A toxicity studies. According to Penniston and Tanumihardjo (2006), "The acute and chronic effects of vitamin A toxicity are well documented in the literature. Emerging evidence suggests that subtoxicity without clinical signs of toxicity may be a growing concern, because intake from preformed sources of vitamin A often exceeds the recommended dietary allowances (RDA) for adults, especially in developed countries. Osteoporosis and hip fracture are associated with preformed vitamin A intakes that are only twice the current RDA... more than 75% of people may be routinely ingesting more than the recommended dietary allowance (RDA) for vitamin A, much of it as preformed vitamin A. Humans as well as other great apes with the most similar metabolic requirements do not store large quantities of preformed Vitamin A, in contrast to the carnivorous and insectivorous species. "Dogs, marmoset monkeys, and foxes, for example, appear to store appreciable amounts of vitamin A in their kidneys, whereas humans and many other primate species do not" (Penniston & Tanumihardjo, 2006).

Penniston and Tanumihardjo (2006) noted: "Fossilized skeletal remains of early humans suggest that bone abnormalities may have been caused by hypervitaminosis A. From these and other reports, vitamin A toxicity is known to be an ancient phenomenon. Several comprehensive reviews and case studies of vitamin A toxicity, which discuss both acute and chronic excess, have been published."

Observational studies have suggested an association between high intakes of preformed vitamin A (more than 1,500 mcg daily--only slightly higher than the RDA), reduced bone mineral density, and increased fracture risk. However, the results of studies on this risk have been mixed, so the safe retinol intake level for this association is unknown.

Total intakes of preformed vitamin A that exceed the UL can cause congenital birth defects... Women who might be pregnant should not take high doses of vitamin A supplements (NIH, 2013).

References:

Dolk, H. M. , Nau , H., Hummler , H. Barlow, S. M. (1999). Dietary vitamin A and teratogenic risk: European Teratology Society discussion paper. European Journal of Obstetrics and Gynecology and Reproductive Biology, 83 . 31 - 36 . http://www.ejog.org/article/S0301-2115(98)00228-0/abstract

Linus Pauling Institute. (2015). Vitamin A. Micronutrient Information Center. Retrieved from: http://lpi.oregonstate.edu/mic/vitamins/vitamin-A

NIH. Vitamin A Fact Sheet for Health Professionals. (2013). National Institutes of Health Office of Dietary Supplements. Retrieved online August 17, 2015 from: https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/

Penniston, K. L. & Tanumihardjo, S. A. (2006). The acute and chronic toxic effects of vitamin A. Am J Clin Nutr. 83 (2). 191-201. http://ajcn.nutrition.org/content/83/2/191.full#cited-by

[juds_j...@yahoo.com]

Hello, i found your post because the same thing happens to me whenever i drink raw kale or spinach. I has a spinach and pineapple smoothie this morning and my eyes were blurry for most of the morning. I also tend to get like a heavy headed feeling and just general fatigue when i have these. might be the oxalates. I don't know but i really want to eat healthier but i better be careful of how i incorporate these.