Purpose <p>Adequate micronutrients play a crucial role in cognitive health. Identifying relevant micronutrients and constructing risk prediction models can guide the prevention of mild cognitive impairment (MCI) in older adults. This study aimed to assess the associations of MCI with whole blood micronutrient levels and develop a nomogram for personalized MCI risk prediction in older adults.</p> Methods <p>In the matched case–control study, 100 MCI patients and 100 matched controls by age, sex and education from Baodi District, Tianjin, China were recruited. MCI was determined by a modified version of the Petersen criteria. Whole blood levels of 9 vitamins and 5 minerals were measured using the dried blood spot technique. Weighted quantile sum regression was employed to identify the most significant micronutrients associated with cognitive function. Receiver operating characteristic (ROC) curves were constructed, and a nomogram for predicting MCI risk was developed.</p> Results <p>High levels of vitamins (vitamin A, vitamin B₂, vitamin B₆, vitamin B₉) and minerals (magnesium, selenium) were significantly associated with lower MCI prevalence, in which vitamin B₂, vitamin B₉ and selenium were ranked as the most significant contributors to cognitive function. The ROC curves for vitamin B₂ and vitamin B₉ (area under the curve = 0.855) have superior diagnostic accuracy compared to individual assessments (<i>p</i> &lt; 0.05). Based on these findings, a nomogram was developed using these two micronutrients to predict MCI risk.</p> Conclusion <p>The nomogram based on vitamin B₂ and vitamin B₉ can be effectively used to detect MCI early and guide preventive strategies in older adults.</p>