Cycling UK Forum

In a world beset by a tsunami of misinformation as well as widespread and systematic fraud, it's so tempting to assume that everything one encounters must be in some way or another, dodgy...
When we turn to look at Zoe, we see an organisation not at first glance so very different from say Theranos. Lot's of big name backers. Money raised and big plans for 'going forward'...
https://newsdirect.com/news/zoe-announc ... -302220194

How much vitamin D is too much?

Given that we're all different weights and with different guts and different metabolisms, I don't think it's easy to say. The figure often quoted is 4000 IU a day. However, finding advice based on decent quality, neutral, science-based data is not easy.
I'm happy to leave my body to generate vit D the natural way, ie from sunlight - and adjust seasonally by adding vit D rich ingredients to my winter diet. They include: mushrooms, eggs and fatty fish - I eat a lot of canned fish, like tuna, salmon, sardines/pilchards, herring & mackerel. Given the disgusting state that fish farms often end up, what with lice and chemicals, I try to stick to wild caught fish. Did you know for example, that it's perfectly legal to sell farmed salmon infected with lice - presumably picked off and flicked into the factory's waste bin, before packaging !! Yuk, yuk, yuk...
https://www.gov.scot/publications/summa ... nd-salmon/

I quite like tinned mackerel in various sauces, good source of vit D or processed to hell?

How much vitamin D is too much?

The oral doses recommended by the NHSs and similar do not produce toxicity.

Toxicity sometimes occurs with much higher doses of over the counter preparations, but is still rare unless large amounts of calcium are also consumed.

(The risks with the particular form of vitamin D used in chronic kidney disease are much greater.)

Jonathan

I quite like tinned mackerel in various sauces, good source of vit D or processed to hell?

That's a good Q. I found this just now:
* Canned pink salmon, drained
A serving of 85 grams or 3 oz provides 12.3 mcg of vitamin D or 61.5% of total daily vitamin D.
* Sardines, canned
A serving of 85 grams or 3 oz of canned sardines provides 4.08 mcg of vitamin D or 20% of total daily vitamin D.
* Tuna, canned in oil
A serving of 85 grams or 3 oz of light tuna, canned in oil, drained solids provides 5.7 mcg of vitamin D, the equivalent of 28.5% daily vitamin D values for an adult.
As mackerel are one of the oilest fish readily available I've hazard a guess that a portion would not fall below 30% and that processing, judging by the above, doesn't necessarily rain on the parade. Eggs come in at around 4 mcg each, ie a typical serving of 2 would provide around 40% of total daily vitamin D.
Crikey - how complicated modern life can turn out to be !!

From the NHS information on Vit D.

"You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you're out in the sun for long periods to reduce the risk of skin damage and skin cancer."
And
"Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years."

However, figures quoted from various places on the internet suggest that half an hour in the sun in June in Spain could generate as much as 4000 IU
So is more than 4000IU considered harmful if taken orally but not from the sun, or does the rate of Vit D generation correlate to time to burn ?

Jdsk wrote: ↑12 Dec 2022, 12:56pm

How much vitamin D is too much?

The oral doses recommended by the NHSs and similar do not produce toxicity.

Toxicity sometimes occurs with much higher doses of over the counter preparations, but is still rare unless large amounts of calcium are also consumed.

(The risks with the particular form of vitamin D used in chronic kidney disease are much greater.)

Jonathan

I believe the serum level of Vitamin K also has a part to play ?

...
Crikey - how complicated modern life can turn out to be !!

Avoiding vitamin D deficiency couldn't be much simpler (for most people)!

Jonathan

Dingdong wrote: ↑12 Dec 2022, 12:54pm I quite like tinned mackerel in various sauces, good source of vit D or processed to hell?

Top 38 items from McCance & Widdowson, (Vitamin D, ug/100g)
There's no tinned mackerel listed, but tinned salmon beats fresh):

210 Oil, cod liver
25 Bloater, flesh only, grilled
19 Herring, flesh only, raw
18.5 Horlicks, powder
18 Roe, cod, hard, raw
16.2 Bloater, flesh only, grilled, weighed with bones and skin
16.1 Herring, flesh only, grilled
16 Herring, pickled
13.6 Salmon, pink, canned in brine, drained
13 Jackfish, raw
13 Sprats, raw
12.8 Eggs, chicken, yolk, raw
12.6 Eggs, chicken, yolk, boiled
12.2 Eggs, chicken, whole, dried
11.8 Salmon, red, canned in brine, skinless and boneless, drained
11.5 Curry, herring, Bengali, homemade
11.1 Kippers, flesh only, boil in the bag, with butter, cooked
11 Salmon, smoked (hot-smoked)
10.9 Herring, flesh only, grilled, weighed with bones and skin
10.9 Salmon, red, canned in brine, drained
10.3 Salmon, wild, baked
10.1 Kippers, flesh only, grilled
10.1 Salmon, wild, grilled
9.8 Salmon, wild, steamed
9.3 Salmon, farmed, flesh only, steamed
9.3 Salmon, farmed, flesh only, steamed, fillets weighed with bones and skin
9.1 Rock Salmon/Dogfish, raw
9 Kippers, flesh only, grilled, fillets weighed with bones and skin
8.9 Salmon, smoked (cold-smoked)
8.8 Baking fat and margarine (75-90% fat), hard block
8.6 Salmon, wild, flesh only, raw
8.5 Mackerel, flesh only, grilled
8.4 Fat spread, low fat (26-39%), polyunsaturated
8.3 Breakfast cereal, malted flake, fortified
8.3 Mackerel, flesh only, grilled, fillets weighed with bones and skin
8.2 Mackerel, flesh only, smoked
8.2 Trout, rainbow, flesh only, baked
8 Mackerel, flesh only, raw

AFAIK the mackerel I'm buying is probably cured in wine or vinegar, and then flavours added. Although tbh I know next to nothing about tinned foods!

I take Vitamin D throughout the year. I commenced this after free screening at work - almost 300 people were tested and over 90% were deficient. My levels were deficient despite it being late summer and my having cycled almost daily all year and eating more than the recommended amounts of fish.

Similar results were found when Sky tested their team. Obviously they were cycling in sunshine more than the rest of us.

I've worked in hospitals in the Nordics quite a lot over the years. You'd expect with the lack of light and cold winter climate their levels would be low. There must be some genetic difference as natives of the area do not have low levels while those moving there do.

You're very wise to supplement.

But vitamin D deficiency was common in Nordic countries. They now have policies on supplementation and fortification. (Which are interestingly different and may not be adequate.)

There are differences between native-born and immigrant residents of Nordic countries. I wouldn't assume that they are genetic.

Jonathan

softlips wrote: ↑12 Jan 2023, 12:06pm I take Vitamin D throughout the year. I commenced this after free screening at work - almost 300 people were tested and over 90% were deficient. My levels were deficient despite it being late summer and my having cycled almost daily all year and eating more than the recommended amounts of fish.

Similar results were found when Sky tested their team. Obviously they were cycling in sunshine more than the rest of us.

I've worked in hospitals in the Nordics quite a lot over the years. You'd expect with the lack of light and cold winter climate their levels would be low. There must be some genetic difference as natives of the area do not have low levels while those moving there do.

Generations of Norwegians have been raised taking daily doses of Möller's Tran, which has about 24 micrograms of vit. D per tablespoon. They also eat quite a bit of fatty fish, and spend more time outdoors, even in winter. In addition, most vitamin D supplements include vitamin K, calcium, magnesium, and zinc, which help your body process vit. D. There is generally good public information about the need for vit. D supplementation, and they have various options for kids who don't like Möller's Tran, such as Vit. D gummy bears.

Jdsk wrote: ↑12 Jan 2023, 12:15pm You're very wise to supplement.

But vitamin D deficiency was common in Nordic countries. They now have policies on supplementation and fortification. (Which are interestingly different and may not be adequate.)

There are differences between native-born and immigrant residents of Nordic countries. I wouldn't assume that they are genetic.

Jonathan

Something to do with the MC1R gene, the same gene associated with red hair.
https://www.nature.com/articles/s41467-018-07691-z