Quick note on the infographic. It is extremely important to not take cod liver oil as your vitamin D source. The problem with cod liver oil is that it contains toxic levels of vitamin A, which acts as an antagonist against vitamin D. They use the same receptor and so when there is too much vitamin A in the blood, even moderate toxicity, the good effects of vitamin D will be greatly diminished.

Also, if you are going to take a multivitamin, make sure it is 100% beta carotene, as other forms of vitamin A (eg. retinol, the kind of vitamin A that cod liver oil contains) cannot be flushed out of the system and will lead to toxicity -- therefore you cancel out any benefit you would have gotten from the D. Below is a more thorough commentary on the latest research:

Dr. John Cannell, MD.
via Vitamin D Council

"Although activated vitamin D and vitamin A signal through common cofactors, they compete for each others function. Retinoic acid antagonizes the action of vitamin D and its active metabolite. In humans, even the vitamin A in a single serving of liver impairs vitamin D's rapid intestinal calcium response. In a dietary intake study, Oh, et al, found that a high retinol intake completely thwarted vitamin D's otherwise protective effect on distal colorectal adenoma, and they found a clear relationship between vitamin D and vitamin A intakes, as the women in the highest quintile of vitamin D intake also ingested around 10,000 IU/d of retinol." [1a, 1b, 1c]

"Furthermore, the consumption of preformed retinol even in amounts consumed by many Americans in both multivitamins and cod liver oil may cause bone toxicity in individuals with inadequate vitamin D status. Women in the highest quintile of total vitamin A intake have a 1.5-times elevated risk of hip fracture." [2]

"Indeed, a recent Cochrane Review found that vitamin A supplements increased total mortality rate by 16%, perhaps through antagonism of vitamin D." [3]

"Another recent Cochrane meta-analysis concluded that although vitamin A significantly reduced the incidence of acute lower respiratory tract infections in children with low intake of retinol, as occurs in the Third World, it appears to increase the risk and/or worsen the clinical course in children in developed countries." [4]

"As early as 1933, Alfred Hess, who discovered that sunlight both prevented and cured rickets warned about vitamin A consumption, concluding, ...as to a requirement of thousands of units of vitamin A daily, the unquestionable answer is that this constitutes therapeutic absurdity, which, happily, will prove to be only a passing fad (p 662)."

"Unfortunately, Hess's prophecy of a passing fad proved premature and Americans continue consuming multivitamins and/or cod liver oil containing small amounts of vitamin D but undesirable quantities of vitamin A. For example, multivitamins, until recently, had small amounts of vitamin D (200 to 400 IU) but high amounts of preformed retinol (5,000 to 10,000 IU). This pales in comparison to a tablespoon of modern cod liver oil, most of which contains sub-physiological amounts of vitamin D (400 to 1200 IU) but supra-physiological amounts of completely preformed retinol (5,000 to 15,000 IU or, in some cases, 30,000 IU)." [5, 6]

"Clinical lore holds that Vitamin A is an anti-infective. We suggest that lore exists because of old cod liver oil studies. Semba reviewed early literature on vitamin A, usually given as cod or halibut liver oil, as a successful anti-infective. For reasons that are not entirely clear, fish liver oils of the time contained much higher amounts of vitamin D then does modern cod liver oil, perhaps because modern processing removes the vitamin D during distillation and then replace it at lower doses. Furthermore, a meta-analysis concluded that vitamin A, when given alone, increases the incidence of respiratory tract infections. If vitamin A increases the risk of respiratory infections, its high content in modern cod liver oils will only mask the full benefit of adequate vitamin D nutrition."

"As the prevalence of vitamin A deficiency in the United States is apparently much lower than the prevalence of subclinical vitamin A toxicity, we cannot recommend cod liver oil for either adults or children. (We exclude fish body oil from our warning, as it contains no vitamin A or vitamin D but is a very important source of omega-3 fatty acids.) For example, in a recent assessment of serum retinyl esters in a group of obese individuals, four percent had levels >10% of total retinol which usually indicates hypervitaminosis A. Instead, a diet rich in carrots, sweet potatoes, cantaloupe, and other orange fruits and vegetables will supply all the carotenoids the body needs to make retinol without the potential for hypervitaminosis A, especially when additional preformed retinol already exists in dairy products, eggs, and fortified cereal. We wish our diet were as rich in vitamin D. With the exception of infants on formula or toddlers drinking large amounts of milk or fortified juice, adequate amounts of vitamin D are virtually impossible to obtain from diet." [7,8,9]

Sources (Gathered by Vitamin D Council http://www.vitamindcouncil.org/newsletter/2008-december.shtm...):

[1a] Calcium and vitamin D intakes in relation to risk of distal colorectal adenoma in women.
http://www.ncbi.nlm.nih.gov/pubmed/17379616

[1b] All-trans retinoic acid antagonizes the action of calciferol and its active metabolite, 1,25-dihydroxycholecalciferol, in rats.
http://www.ncbi.nlm.nih.gov/pubmed/15987844

[1c] Vitamin A antagonizes calcium response to vitamin D in man.
http://www.ncbi.nlm.nih.gov/pubmed/11585356

[2] Vitamin A intake and hip fractures among postmenopausal women.
http://www.ncbi.nlm.nih.gov/pubmed/11754708

[3] Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases.
http://www.ncbi.nlm.nih.gov/pubmed/18425980

[4] Vitamin A for preventing acute lower respiratory tract infections in children up to seven years of age.
http://www.ncbi.nlm.nih.gov/pubmed/18254093

[5] The acute and chronic toxic effects of vitamin A
http://www.ncbi.nlm.nih.gov/pubmed/16469975

[6] Vitamin A as "anti-infective" therapy, 1920-1940.
http://www.ncbi.nlm.nih.gov/pubmed/10203551

[7] Vitamin A supplementation and childhood morbidity from diarrhea and respiratory infections: a meta-analysis.
http://www.ncbi.nlm.nih.gov/pubmed/12640379

[8] Evaluation of vitamin A toxicity
http://www.ncbi.nlm.nih.gov/pubmed/2197848

[9] Retinol to retinol-binding protein (RBP) is low in obese adults due to elevated apo-RBP.
http://www.ncbi.nlm.nih.gov/pubmed/18641048