Large Vitamin D website in Germany
English version which is a small subset of
German Version
German Version in English (2 clicks to translate to 53 other languages)
English version of the website looks like:

Nice Word Cloud on their home page

Symptoms of vitamin D deficiency
Feel:
Weakness: I often feel weak.
Sadness: I often feel sad.
Listlessness: I often feel listless.
Tiredness: I often feel tired.
Muscle
Eyelid twitching: I have twitching or spasms of my eyelid.
Arm twitching: I have twitching or spasms of my arms or hands.
Legs twitching: I have twitching or spasms of my legs.
Cramps: I have cramps of one calf or both calves.
Cramps at Night: I have twitching or spasms especially at night-time.
Dizzy
Circulation-Problems: I can't see anymore or feel dizzy when I stand up quickly.
Dizzyness on Exertion: I can't see anymore or feel dizzy with an exertion like climbing stairs.
Vertigo: I can't see anymore or feel dizzy but I recover when I lie down.
Nausea
Nausea: I am suffering from nausea when I stand up quickly.
Nausea on exertion: I am suffering from nausea at exertion.
Nausea - improving: I am suffering from nausea but it gets better, when I lie down.
Pain
Muscle-Pain: I have muscle pain of my neck.
Headache - Getting up: I get a headache when I suddenly get up.
Headache - Always: I have headache nearly all day and night.
Headache - Sport: I get a headache at sports
Headache - disappears: I have headache, but it disappears, when I lie down.
Backpain: While standing a long time I have a pain in my low back.
Hip - pain: While standing a long time I feel pain in my hips.
Groin - Pain: While standing a long time I have groin pain
Legs - Pain: While standing a long time I feel pain of my legs
Feet - Pain: While standing a long time i feel pain in my feet
Allergies: I am suffering from several allergies.
- Sneezing: I often have to sneeze
Sun
Sun Allergy: Midday sun makes me feel uncomfortable and I get allergic reactions to the sun.
Headache - Sun: Midday sun makes me feel uncomfortable and I get headache staying in the sun.
Circulation - Problems - Sun: I feel uncomfortable in the midday sun I get circulation problems.
Sun Avoidance: Sun at noon-time causes problems and I to avoid staying in the sun.
Fingernails small white spots, dots or cross lines
Cold: I easily come down with a a cold